A cement and concrete industry publication

User Guide to RC Spreadsheets: v4 (Addendum to v3)

User Guide to Excel Spreadsheets for reinforced concrete design to BS EN 1992:2004 Part 1-1 and its UK National Annex (incl AMD 1) and BS 8110: Part 1, 1997 (incl Amd 4)

C H Goodchild BSc CEng MCIOB MIStructE

R M Webster CEng FIStructE

ForewordThis 4th edition or version 4 of the User Guide to the RC Spreadsheets is intended to be read as an addendum to the version 3 publication[1] published in July 2006. This 4th edition covers revisions to the Eurocode series of spreadsheets (produced by The Concrete Centre) that have proved necessary following publication of amendment AMD 1 to the UK National Annex to Eurocode 2 in December 2009 and subsequent withdrawal of BS 8110 in March 2010. It also formally introduces five new spreadsheets in the Eurocode series and gives additional commentary on others.

RC-spreadsheets:v4 is intended to help with the rapid production of clear and accurate design calculations for reinforced concrete elements to both Eurocode 2 and BS 8110-1:1997.

The first version of this publication and the spreadsheets were produced by the Reinforced Concrete Council (RCC). Since its release in 2000 the spreadsheets have proved enormously popular and have been maintained by the RCC and its successor, The Concrete Centre.

AcknowledgementsThe ideas and illustrations come from many sources. The help and guidance received from many individuals are gratefully acknowledged.

Thanks are due to members of the original projects Advisory Group for their time and effort in helping to make the project feasible and in bringing it to fruition. The members of the Advisory Group are listed on the inside back cover.

TCC55X Axial Column Shortening (24 storeys) was sponsored by Adams Kara Taylor.

Published by MPA - The Concrete Centre

Riverside House, 4 Meadows Business Park, Station Approach, Blackwater, Camberley, Surrey GU17 9AB Tel: +44 (0)1276 606800 Fax: +44 (0)1276 606801

CCIP-053. Published August 2010. MPA - The Concrete Centre

User Guide v1 published by the British Cement Association on behalf of the Reinforced Concrete Council.

User Guide v2 published electronically by The Concrete Centre.

User Guide v3 published by The Concrete Centre. CCIP-008 - July 2006

CCIP publications are produced on behalf of the Cement and Concrete Industry Publications Forum an industry initiative to publish technical guidance in support of concrete design and construction.

CCIP publications are available from the Concrete Bookshop at www.concretebookshop.comTel: +44 (0)7004 607777

All advice or information from MPA - The Concrete Centre is intended for those who will evaluate the significance and limitations of its contents and take responsibility for its use and application. No liability (including that for negligence) for any loss resulting from such advice or information is accepted by MPA - The Concrete Centre or their subcontractors, suppliers or advisors. Readers should note that MPA - The Concrete Centre publications are subject to revision from time to time and should therefore ensure that they are in possession of the latest version.

User Guide to RC Spreadsheets: v4 (Addendum to v3)

Contents

CONTENTS IN FULL AND LOCATION OF GUIDANCE 2

INTRODUCTION 4

GENERAL NOTES 6

USING THE SPREADSHEETS 8

AMENDMENTS TO V3 SPREADSHEET DESCRIPTIONS 9

ADDITIONAL SPREADSHEETS TO EUROCODE 2 11

TCC15 Axially Loaded Walls and Columns 11

TCC22 FE Assistant 12

TCC55X Axial Column Shortening 14

TCC62 Retaining Wall Design 16

TCC63 Core Wall Design 21

TCC94 Two Way Slab 24

REFERENCES 27

1

Contents

User Guide

v3 v4

INTRODUCTION 1 4

GENERAL NOTES 3 6

Using the spreadsheets 10 8

Amendments to V3 spreadsheet descriptions 9

Menu.xls 16

SPREADSHEETS TO EUROCODE 2 179 11

General notes to Eurocode 2 versions 181

Elements TCC11 Element Design.xls 185

TCC12 Bending and Axial Force.xls 194

TCC13 Slab Punching.xls 196 9*

TCC14 Crack Width.xls 201

TCC15 Resistance of Axially Loaded Walls/Slabs 11

Analysis TCC21 Subframe Analysis.xls 205

TCC22 FE Assistant 12

Slabs TCC31 One-way Slabs.xls 208

TCC31R Rigorous One-way Slabs.xls 214

TCC32 Ribbed Slabs (A&D).xls 221

TCC33 Flat Slabs (A&D).xls 228

TCC33X Flat Slabs (A&D).xls 237

Beams TCC41 Continuous Beams.xls 243 9*

TCC41R Rigorous Continuous Beams.xls 249

TCC42 Post-tensioned Analysis & Design.xls (Beta) 256

TCC43 Wide Beams (A & D).xls 264

Columns TCC51 Column Load Take-down Design.xls 270

TCC52 Column Chart generation.xls 276

TCC53 Column Design.xls 278

TCC54 Circular Column Design.xls 280

TCC55 Axial Column Shortening.xls 282 10*

TCC55X Axial Column Shortening (24 storeys) 14

Walls TCC62 Retaining Wall Design.xls 16

TCC63 Core Wall Design 21

Stairs TCC71 Stair Flight & Landing - Single.xls 284

Foundations TCC81 Foundation Pads.xls 287

TCC82 Pilecap Design.xls 291

Tabular versions TCC94 Two Way Slab 24

Contents in full and location of guidance

Contents in full and location of guidance in User Guides to RC Spreadsheets: v3 and v4

2

* Amendment

Contents in full and location of guidance

User Guide

v3 v4

SPREADSHEETS TO BS 8110 17

Elements RCC11 Element Design.xls 19

RCC12 Bending and Axial Force.xls 26

RCC13 Punching Shear.xls 28

RCC14 Crack Width.xls 33

Analysis RCC21 Subframe Analysis.xls 35

Slabs RCC31 One-way Solid Slabs (A & D).xls 38

RCC31R Rigorous One-way Slabs.xls 43

RCC32 Ribbed Slabs (A & D).xls 50

RCC32R Rigorous Ribbed Slabs.xls 56

RCC33 Flat Slabs (A & D).xls 64

Beams RCC41 Continuous Beams (A & D).xls 72

RCC41R Rigorous Continuous Beams (A & D).xls 78

RCC42 Post-tensioned Slabs & Beams (A & D).xls 85

RCC43 Wide Beams (A & D).xls 107

Columns RCC51 Column Load Take-down & Design.xls 113

RCC52 Column Chart generation.xls 118

RCC53 Column Design.xls 120

RCC54 Circular column charting.xls 123

Walls RCC61 Basement Wall.xls 125

RCC62 Retaining Wall.xls 132

Stairs RCC71 Stair Flight & Landing - Single.xls 139

RCC72 Stairs & Landings - Multiple.xls 142

Foundations RCC81 Foundation Pads.xls 146

RCC82 Pilecap Design.xls 149

Tabular versions RCC91 One-way Solid Slabs (Tables).xls 158

RCC92 Ribbed Slabs (Tables).xls 161

RCC93 Flat Slabs (Tables).xls 166

RCC94 Two-way Slabs (Tables).xls 173

RCC95 Continuous Beams (Tables).xls 175

ADMIN FOLDER 298

REFERENCES AND FURTHER READING 299 27

3

The RC spreadsheets were originally produced under the Reinforced Concrete Councils project, Spreadsheets for concrete design to BS 8110 and EC2. They were released in January 2000 and have been maintained and extended by the RCC and its successor The Concrete Centre. They continue to be supported by The Concrete Centre.

Version 4 of the User Guide covers version 4 of the spreadsheets. The Concrete Centre series of spreadsheets have been updated in line with amendment 1 of the UK National Annex to Eurocode 2 in December 2009. Whilst BS 8110 was withdrawn by BSI early in 2010, it was recognised that some projects and indeed some practitioners may wish to continue using this standard in the short to medium term. Thus the RCC series of spreadsheets have been updated and are reissued.

In 2006, the introduction of Eurocode 2[2], its National Annex and Amendment of BS 8110:1997[3] necessitated the revision of all the spreadsheets produced to that date and the publication of version 3 of the User Guide. The third edition of the User Guide provided guidance on the use of all spreadsheets produced to July 2006.

The vast majority of version 3 of the User Guide remains valid and the decision was made that version 4 should take the form of an addendum to version 3. Therefore only those areas that are significantly different or new are contained in version 4. For instance, version 4 formally introduces five new spreadsheets to the Eurocodes. Detailed descriptions of the majority of spreadsheets will be found in version 3 of the User Guide.

For the experienced engineer, the spreadsheets allow the rapid production of clear and accurate design calculations. The spreadsheets allow younger users to understand concrete design and help them to gain experience by studying their own what if scenarios. The individual user should be able to answer his/ her own questions by chasing through the cells to understand the logic used. Cells within each spreadsheet can be interrogated and can have their formulae checked and values traced. The original spreadsheets reflected a consensus of opinion on several design issues. The version 3 Eurocode 2 spreadsheets reflected a consensus of opinion of a limited number of engineers. Version 4 Eurocode spreadsheets benefit from a few years use - students and young engineers may follow the model calculations presented in the spreadsheets to form an understanding of current reinforced concrete design.

The spreadsheets are intended to follow normal design practice and cater for the design of low- to medium-rise multi-storey concrete framed buildings. They are offered as shareware. However, users are required to register when using them in any commercial capacity*.

The original project was jointly funded by the RCC and the Department of the Environment Transport and the Regions (DETR) under its Partners in Technology scheme. It was made possible by the support and contributions of time given by individual members of industry. The project was managed by the RCC and guided by an 80-strong Advisory Group of interested parties, including consulting engineers and software houses.

In producing the original spreadsheets several issues had to be addressed. Firstly, which spreadsheet package should be used? Excel ( Microsoft Corporation) appeared to hold about 70% of the market amongst structural engineers and was thus adopted. More specifically, Excel 97 was originally adopted as being de facto the most widely available spreadsheet in the field. To avoid complications, it was decided not to produce corresponding versions using other spreadsheet packages. The spreadsheets are compatible with later versions of Excel.

Whilst the spreadsheets to BS 8110 provide a consensus of current commercial reinforced concrete design practice, the spreadsheets to Eurocode 2, provide a consensus of design procedures to this new design code. The introduction of Eurocode 2 will provide commercial opportunities for those who are prepared to use it. The spreadsheets should help with the transition between Eurocode 2 and BS 8110.

It is believed that both novices and experienced users of spreadsheets will be convinced that spreadsheets have a great potential for teaching BS 8110 and Eurocode 2, improving concrete design and, above all, improving the concrete design and construction process.

Version 2.xThe version 2.x released in 2003[4] introduced new spreadsheets to BS 8110, to the more finalised EN 1992-1-1 (Eurocode 2) and an overarching menu spreadsheet. Previously issued spreadsheets to BS 8110 were updated.

Introduction

4

* Registration is through The Concrete Bookshopwww.concretebookshop.com

Introduction

The new spreadsheets introduced were:

Menu

BS 8110

RCC31R Rigorous One-way Slabs RCC32R Rigorous Ribbed Slabs RCC41R Rigorous Continuous Beams RCC43 Wide Beams (A&D) RCC54 Circular Column Design RCC82 Pilecap Design

Eurocode 2

RCCen11 Element Design RCCen12 Bending and Axial Force RCCen13 Punching Shear RCCen14 Crack Width RCCen21 Subframe analysis RCCen31 One-way Solid Slabs (A & D) RCCen31R Rigorous* One-way Solid Slabs RCCen32 Ribbed Slabs (A & D) RCCen33 Flat Slabs (A & D) RCCen41 Continuous beams (A & D) RCCen41R Rigorous* Continuous Beams RCCen43 Wide Beams (A&D) RCCen52 Column Chart generation RCCen53 Column Design RCCen55 Axial Column Shortening RCCen81 Foundation Pads RCCen82 Pilecap Design

Version 3The release of version 3 of the spreadsheets followed the publication of BS EN 1992-1-1 (Eurocode 2)[2] and the UK National Annex and the publication of Amendment 3 to BS 8110 Part 1: 1987. The requirements within these documents necessitated the revision of all previously published spreadsheets. The opportunity was taken to introduce new spreadsheets as follows:

BS 8110

RCC82 Pilecap Design

Eurocode 2

TCC33X Flat Slabs (Whole floor) TCC41R Rigorous Continuous Beams TCC42 Post-tensioned Slabs and Beams

(A&D) (b version)

TCC43 Wide Beams (A&D) TCC54 Circular Column Charting

TCC71 Stair Flight and Landing - single TCC81 Foundation Pads TCC82 Pilecap Design

Spreadsheets numbered RCCen11, RCCen12 etc released as Beta versions were released for use as TCC11, TCC12 etc.

Version 4The release of version 4 of the spreadsheets follows the publication of amendment AMD 1 of the UK National Annex to Eurocode 2 to BS EN 1992-1-1 (Eurocode 2)[2] Whilst BS 8110 was withdrawn by BSI early in 2010, it was recognised that some projects and indeed some practitioners may wish to continue using this standard in the short to medium term. Thus the RCC series of spreadsheets have been updated and are reissued. The opportunity has been taken to formally introduce new spreadsheets as follows:

Eurocode 2

TCC15 Resistance of Axially Loaded Walls/slabs TCC22 FE Assistant TCC62 Retaining Wall Design TCC63 Core Wall Design TCC94 Two Way Slab

Using and improving the spreadsheetsSince their release in 2000 the spreadsheets have proved to be enormously popular. They may now be regarded as having now been thoroughly tested by engineers in practice but this does not mean that they are infallible! The user is referred to Managing the spreadsheets and other General Notes that follow.

The usefulness and robustness of previous spreadsheets have been enhanced by user feedback. Please email helpdesk@concretecentre.com with any suggestions or comments. Comments or suggestions for improvement are welcomed. Contact The Concrete Centres Helpdesk at helpdesk@concretecentre.com.

5

Managing the spreadsheets

UseSpreadsheets can be a very powerful tool. Their use has become increasingly common in the preparation of design calculations. They save time, money and effort. They provide the facility to optimise designs and they can help instill experience. However, these benefits have to be weighed against the risks associated with any endeavour. These risks must be recognised and managed. In other words appropriate levels of supervision and checking, including self-checking, must, as always, be exercised when using these spreadsheets.

AdvantagesFor the experienced engineer, the spreadsheets help in the rapid production of clear and accurate design calculations for reinforced concrete elements. The contents are intended to be sufficient to allow the design of low to medium-rise multi-storey concrete framed buildings.

Spreadsheets allow users to gain experience by studying their own what if scenarios. Should they have queries, individual users should be able to answer their own questions by chasing through the cells to understand the logic used. Cells within each spreadsheet can be interrogated, formulae checked and values traced. Macleod[8] suggested that, in understanding structuralbehaviour, doing calculations is probably not a great advantage; being close to the results probably is.

Other benefits include quicker and more accurate reinforcement estimates, and the possibilities for electronic data interchange (EDI). Standardised, or at least rationalised, designs make the checking process easier and quicker.

Appropriate use

In its deliberations[9] the Standing Committee on Structural Safety (SCOSS) noted the increasingly wide-spread availability of computer programs and circumstances in which their misuse could lead to unsafe structures.

These circumstances include:

People without adequate structural engineering knowledge or training may carry out the structural analysis.

There may be communication gaps between the design initiator, the computer program developer and the user.

A program may be used out of context. The checking process may not be sufficiently

fundamental.

The limitations of the program may not be sufficiently apparent to the user.

For unusual structures, even experienced engineers may not have the ability to spot weaknesses in programs for analysis and detailing.

The committees report continued: Spreadsheets are, in principle, no different from other software With regard to these spreadsheets and this publication, The Concrete Centre hopes to have addressed more specific concerns by demonstrating clear evidence of adequate verification by documenting the principles,theory and algorithms used in the spreadsheets. The spreadsheets have also had the benefit of the Advisory Groups overview and inputs. Many, especially the spreadsheets to BS 8110, have had several years use and maintenance. Inevitably, some unconscious assumptions, inconsistencies, etc. will remain.

LiabilityA fundamental condition of use is that the user accepts responsibility for the input and output of the computer and how it is used.

As with all software, users must be satisfied with the answers these spreadsheets give and be confident in their use. These spreadsheets can never be fully validated but have been through Beta testing, both formally and informally. However, users must satisfy themselves that the uses to which the spreadsheets are put are appropriate.

ControlUsers and managers should be aware that spreadsheets can be changed and must address change control and versions for use. The flexibility and ease of use of spreadsheets, which account for their widespread popularity, also facilitate ad hoc and unstructured approaches to their subsequent development.

Quality Assurance procedures may dictate that spreadsheets are treated as controlled documents and subject to comparison and checks with previous methods prior to adoption. Users Quality Assurance schemes should address the issue of changes. The possibilities of introducing a companys own password

6

General notes

General Notes

to the spreadsheets and/ or extending the revision history contained within the sheet entitled Notes! might be considered.

Application

The spreadsheets have been developed with the goal of producing calculations to show compliance with codes. Whilst this is the primary goal, there is a school of thought[9] that designers are primarily paid for producing specifications and drawings that work on site and are approved by clients and/ or checking authorities. Producing calculations happens to be a secondary exercise, regarded by many experienced engineers as a hurdle on the way to getting the project approved and completed. From a business process point of view, the emphasis of the spreadsheets might,in future, change to establishing compliance once members, loads and details are known. Certainly this may be the preferred method of use by experienced engineers.

The spreadsheets have been developed with the ability for users to input and use their own preferred material properties, bar sizes and spacings, etc. However, user preferences should recognise moves for efficiency through standardisation.

Another long-term objective is automation. To this end, spreadsheet contents might in future be arranged so that input and output can be copied and pasted easily by macros and/ or linked by the end-user. There are counter arguments about users needing to be closer to the calculations and results in order to ensure they are properly considered see Appropriate use on the previous page.

We emphasise that it is up to the user how he/ she uses the output. The spreadsheets have been produced to cater for both first-time users and the very experienced without putting the first-time user off. Nonetheless, their potential applications are innumerable.

Summary

With spreadsheets, long-term advantages and savings come from repeated use but there are risks that need to be managed. Spreadsheets demand an initial investment in time and effort, but the rewards are there for those who make the investment. Good design requires sound judgement based on competence derived from adequate training and experience, not just computer programs.

For further general notes on use, familiarisation and layout of the spreadsheets the user is urged to consult the handbook to version 3, to which this booklet is an addendum.

7

Frequently Asked Questions

Macros

When loading the individual spreadsheets, Excel may warn about the presence of macros. All the macros provided in the files are either to allow automated printing of the calculations or to provide choices by way of combo-boxes. The printing macros have been assigned to buttons. Turning the macros off may affectthe actual function of the spreadsheets but will certainly make printing of the sheets as configured more difficult and make the choice of options very much more difficult.

Fonts

Unless the appropriate fonts Tekton and Marker (supplied in the CD-ROM) have been installed by the user, the appearance on screen will be different from that intended. These upright fonts have been used to emulate a designers handwriting and to allow adequate information to be shown across the page and in each cell.

If problems are experienced it is most likely that the fonts on your computer screen will have defaulted to the closest approximation of the fonts intended (e.g. the toolbar may say Tekton but a default font such as Arial will have been used). The spreadsheets will work but not as intended ends of words may be missing, numbers may not fit cells resulting in a series of hashes, #####. Column width and cell overlap problems only occur when the correct fonts are not loaded.

It is strongly recommended that the Tekton and Marker fonts are copied into your computers font library. The Freeware fonts may be found in the Fonts folder on the CD-ROM.

They may be copied in the following manner, either:

Start/Settings/Control Panel/Fonts/ File/ Add Fonts and when asked copy fonts to system directory? answer yes.

or

Through Microsoft Explorer and copying (or dragging) the font files into your font library, usually contained in Windows/ Set-up/ Fonts

Help

A printed copy of this User Guide is available from The Concrete Bookshop www.concretebookshop.com. The User Guide is also available as an Adobe Acrobat file User Guide pdf (on the CD-ROM). A copy of Adobe Acrobat Reader will be required to read this file.

Help is also available at the following places:

Within Excel under Help to the right hand side of the spreadsheets, cells under Operating Instructions contain help and error messages.

Queries may be emailed to helpdesk@concretecentre.com. Preference will be given to those who have registered.

Support

Any questions, comments, developments and suggestions are welcomed. Please email them to helpdesk@concretecentre.com.

Preference will be given to those who are registered, as detailed above.

Availability/registration

The spreadsheets may not be used for commercial purposes until the user has purchased and validated a licence. Licences may be purchased from The Concrete Bookshop www.concretebookshop.com or via The Concrete Centre website. Licences may be validated via www.concretecentre.com/rcspreadsheets. The purchase price includes:

Permission to use the spreadsheets for commercial purposes for at least one year

A hard copy of this publication and User Guide to RC Spreadsheets: v3

CD-ROM containing RC Spreadsheets: v4, together with Admin files, which themselves contain fonts, issue sheets, user guide files etc.

Occasional e-mails to inform registrants of any revisions or changes to the spreadsheets or other relevant information

Details of how to download updates of the spreadsheets

Preferential treatment with regard to support

Further information, updates, FAQs, free trial download versions of some spreadsheets, latest news and other information on the RC-Spreadsheet suite is available on www.concretecentre.com/rcspreadsheets

Overseas use

The spreadsheets have been developed and maintained for use within the UK. The Concrete Centre reserves the right to pass details of non-UK registrants to any future owner of the non-UK copyright or overseas distributor of the spreadsheets.

Updates

Registrants will be provided with information on how to download updates.

8

Using the spreadsheets

Amendments to v3 spreadsheet descriptions

Users should be aware of the following changes to the descriptions given in version 3 of the User Guide.

All TCC spreadsheetsAll of the TCC series of spreadsheets to Eurocode 2 have been revised in line with amendment AMD 1 of the UK National Annex to Eurocode 2 published in December 2009. They have also been rebranded to reflect The Concrete Centre becoming part of The Mineral Products Association.

Changes to the National Annex included:

Use of BS 8500 for recommendations for concrete quality for a particular exposure class and reinforcement cover.

Values of k1 and k

2 in Cl 4.4.1.3(4) (cover to

foundations rationalised)

Limiting value of cot y where shear coexists with applied tension

Strength reduction factor for concrete cracked in shear (v

1 in Cl 6.2.3(3))

Limit of vED < 2 v

Rdc at the first punching shear

perimeter (Cl 6.4.5(4))

Spacing of links in columns using concrete stronger than C50/60

Clarification of crack width calculation (Table NA.4)

Revisions to span : depth verification of deflection (Table NA.5, Notes 5 and 6)

Details of changes to individual spreadsheets may be found in the Notes! sheet of each spreadsheet or within the latest version of Spreadsheet Issue sheet .xls within the ADMIN folder. Changes to span : depth and punching shear calculations caused the more major amendments to the spreadsheets. Amendments that warrant further discussion are outlined below.

It should be noted that the encastr option available in many spreadsheets is intended to enable modelling of continuity of more than 6 spans.

All RCC spreadsheetsAll RCC spreadsheets have been subject to minor revisions and have been rebranded to reflect The Concrete Centre becoming part of The Mineral Products Association. These spreadsheets are suitable for design calculations to the now withdrawn BS 8110 (up to and including Amendment 4).

TCC13 Slab Punching.xlsVersion 4 has been updated to revised UK National Annex.

In version 4, the options for determining the shear enhancement factor b have been changed. Insteadof a choice between the using the default factors to Clause 6.4.3(6) of EC2 and a manual input ofbV

Ed, one can now choose either the default factors or

to calculate b by inputting additional data.

The methods used for determining b are described in Clauses 6.4.3(3) for internal columns, 6.4.3(4) for edge columns and 6.4.3(5) for corner columns. However at the time of writing [July 2010], there is a gap in the perimeter column clauses in that no method is given for calculating U

1* when the slab edge does not align

with the outside face of the column. This omission has been queried with BSI committee B525/2, but in the meantime, the following assumptions have been made:

Slab edge outside column - U1* unchanged

but U1 increases.

Slab edge inside column - U1* unchanged

but MIN[1.5d, 0.5C1] replaced by MIN[1.5d,

0.5(C1 inset)].

If the Eurocode 2 committee decide that a differing method is more appropriate in these situations, the spreadsheet will of course be updated. In the meantime, we are confident that the methods currently used are safe to use.

Other recent changes to this spreadsheet include:

vEd,max

corrected to 0.5vfcd

Correction to edge column face shear when hole on North face of column.

New routine for hole reductions at column faces.

In the determination of punching shear stresses, Version 4 deducts loads within the loaded area.

TCC41 Continuous Beam (A & D).xlsTCC41 now uses a tension flange width for span top steel if a span hogs between 0.4L and 0.6L; otherwise bw is selected. The mid span tension flange width has

been set to the average bt of the supports at either

end. This seems to give the best detailing arrangement both for cantilevers and normal spans. An extra line has been added for each span on the SPANS page, so the user knows what width to place the top steel within.

Amendments to v3 spreadsheet descriptions

9

TCC55 Axial Column ShorteningFollowing the release of TCC55 a number of enquiries were received which resulted in the following FAQ being released giving additional guidance for the axial column shortening spreadsheet.

Q1: If I have a building less than 11 storeys how is the information input? Is the load just input as zero on the upper floors?

A1: No start at the top, and leave the bottom line blank.

Q2: If I have a building of 10 storeys, taking 14 days construction per floor, giving 140 days to occupancy. How could I look at the effects say, mid way through construction?

A2:The plot of vertical displacement on the RESULTS page is the amount of displacement occurring after the floor at the indicated level is cast. Ie. it may be that the slab should be constructed this amount high. You should not need any other value. It is the differential between adjacent columns/walls that can be critical, but remember that moments induced by differential shortening will redistribute column reactions, so this effect should not be neglected.

Q3: Would I adjust the days to occupancy figure to reflect the moment in time I want the results for?

A3: No this will not work. This input only fixes when the permanent portion of the imposed loading is applied.

Q4: Finally (and most importantly..), is the spreadsheet available for an increased number of floors? We are currently about to start construction on a 35 storey building where creep may be an issue with respect to the cladding package. Would it be possible to obtain aspreadsheet of this size?

A4: TCC55X which has input for 24 storeys is included in the spreadsheet package. To go higher than this, storeys can be grouped together if care is taken with the input.(See TCC55X)

10

11

TCC15.xls determines the flexural and shear resistances of slab or wall sections at both ULS and SLS for given values of axial stress and permissible maximum crack width. It also generates a plot of axial stress against moment for the section and a design table for varying levels of primary reinforcement.

MAIN!This single sheet contains of all of the main input for materials and section data. Environmental details and age at loading are also input as these are required to calculate the creep factors that determine SLS behaviour.

For the given parameters, moment and shear resistances are given together with a value of the SLSneutral axis depth, as this may affect the permissible maximum crack with to BS EN 1992-3.

The chart at the bottom of this page shows resistance curves for both the ultimate and service conditions.

TABLE!On this sheet a table of resistances for varying amounts of primary reinforcement can be generated by clicking the macro button. A warning message appears if the data displayed do not match those on the MAIN! page.

Calcs!This page contains the calculations required to generate the results. These are quite complex at SLS where there are a variety of limiting conditions.

Ref!Ref! Defines the values of various parameters used in the spreadsheet.

Notes!This sheet gives disclaimers and revision history.

TCC15 Resistance of Retaining Members.xls

TCC15 Resistance of Axially Loaded Walls / Slabs / MAIN!

TCC15 Resistance of Retaining Members.xls

12

This spreadsheet provides values of creep factors, concrete tensile strengths and free shrinkage strains for use with finite element slab design programs that take account of concrete cracking (non-linear analysis). The methods used are those recommended in Concrete Society Technical Report No TR58, Deflections in concrete slabs and beams. With programs that do not account for cracking, creep factors substantially HIGHER than those calculated by this spreadsheet should be employed, to allow for the increased displacements caused by cracking and shrinkage.

Both creep factors and concrete tensile strength are related to the loading history of a member, and are also dependent upon relative humidity, ambient temperature, cement type and member geometry (equivalent thickness). The characteristic cylinder strength of the concrete (fck) is also required. The user should note that this should be the actual characteristic strength, which may well be higher than that specified from minimum strength specifications.

h, fct, e!

This single sheet consists of all of the main input and output. Most inputs, which are in blue and underlined, should be self-explanatory. In addition to the loading history and the inputs mentioned above, there is a switch which allows for construction loading from a slab above to be taken into account. In many instances, this temporary construction loading will determine the critical values required for FE design.

In the results section values are given for both the direct concrete tensile strength f

ctm, and the

flexural tensile strength fctm,fl

. The user should make a judgement between these two values, depending upon the degree of restraint that may be present.

There are several explanatory notes and hints at the right hand side of this page.

Calculations!Calculations! provides the detailed derivations for the combined creep factor h, autogenous and free shrinkage strains e

ca and e

ed, and critical concrete

tensile strength fctm(t)

.

Notes!This sheet gives disclaimers and revision history.

TCC22 FE Assistant.xls

TCC22 FE Assistant /h, fct, e!

13

TCC22 FE Assistant /h, fct, e!

TCC22 FE Assistant/Calculations!

14

TCC55X Axial Column Shortening / MAIN!

This spreadsheet works out axial column shortenings exactly as TCC55, except that it will cater for up to 24 storeys. As it is a larger file, it has been included as a separate spreadsheet.

The pages in this spreadsheet are as TCC55, except that results are now located on a new RESULTS! page in order to gain space.

Operation is identical to spreadsheet TCC55, except that at the top of the MAIN! page, it is now possible to enter three different phases for the application of the permanent portion of the imposed loading.

TCC55X Axial Column Shortening.xls

TCC55X Axial Column Shortening.xls

15

TCC55X Axial Column Shortening / RESULTS!

TCC62.xls designs simple retaining walls with stems up to 3.0 m high. While section design is to Eurocode 2, this spreadsheet has been developed using the geotechnical rules and methods contained in Eurocode 7[5]. In particular, reference has been made to TCC How to leaflets number 8 Foundations and number 9 Retaining Walls[6]. The approach is very different from that of the earlier BS8110 spreadsheet (RCC62). Instead of comparing characteristic pressures with a permissible maximum value, two ultimate combinations of actions are employed together with two sets of factored resistances.

The spreadsheet is intended to cover only short walls and to help general engineers who, from time to time, design retaining walls as part of a wider interest in structures rather than the specialists. The 3.0 m wall height is an arbitrary limit set for short wall which is intended to cover over 90% of the cases encountered in general structural designs. Although many of the design principles still apply to higher walls, criteria such as wall movements and the validity of the assumptions made (e.g. no wall friction or inadequate drainage behind the wall) require further consideration and investigation. The spreadsheet does not cover embedded (e.g. contiguous bored pile) retaining walls.

The effects of compaction pressures are considered for the wall stem design, but because of their short-term and localised nature, they are not considered to be critical in terms of bearing or sliding.

Stability analysis is done about the toe of the base. (Stability analysis taken about toe of nib is ignored; the nib is a section sticking down from general level of the base, and stability analysis about its toe can give strange answers). Global slope stability checks are not undertaken in the spreadsheet and should be addressed using other means. Input is required only on the first sheet.

DATA!This single sheet consists of all of the main inputs. Most inputs, which are in blue and underlined, shouldbe self-explanatory. The key diagram at the top of the sheet defines most input parameters. The active diagram below serves as a visual check on geometric data. Operating instructions and error messages are shown in column L: hints on sizing are given at L26:L39. The lower ground level must be at least level with the top of the base. Covers required are nominal covers to bending reinforcement.

The designer should determine the characteristic soil parameters from the Site Investigation Report, local knowledge or for estimation purposes from appropriate text or guidance*. Related design properties are then automatically derived using the two sets of partial load and material factors according to the UK National Annex to BS EN 1997. Thus, Combination 1 and Combination 2 values of earth pressure coefficients and factored loads are calculated. Formulae for each property and action are shown at the right hand side of the sheet.

In determining earth pressures, the simplified Rankines formula for smooth vertical walls has been employed (calculation model A in How To leaflet 9). However when the heel projection, b

h is too small to strictly

meet Rankine criteria, reduced values of c (angles of active thrust to horizontal) are used. For the calculation of ultimate bearing pressures, rectangular stress blocks are used.

The spreadsheet is based on a number of assumptions which should be assessed as being true or erring onthe safe side in each case. These are:

Wall friction is zero Granular backfill is used. Even a small value

of effective cohesion, c, can significantly reduce active pressures. However, to acknowledge the fact that many retaining walls are built with granular backfill for drainage and to err on the side of caution, the spreadsheet assumes only cohesionless materials.

The spreadsheet does not include checks on rotational slide/ slope failure. The location of any nib influences potential slip planes.

The spreadsheet check on deflection of the wall does not include that due to base rotation.

The spreadsheet is not intended for walls over 3.0 m high.

The spreadsheet includes for concrete self weight.

Adequate drainage system is provided behind the wall.

Checks for temperature/shrinkage effects are not included.

The spreadsheet does not include checks on the effects of seepage of ground water beneath the wall.

Many engineers have reservations about including the effect of passive pressure in front of the wall so a combo box is provided at cell L16, where the inclusion of passive pressure can be switched on or off. Where passive pressure is allowed, an allowance for unplanned excavation in front of the base is made in

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TCC62 Retaining Wall.xls

TCC62 Retaining Wall.xls

determining the height of the passive pressure, hp. In

accordance with BS EN 1997-1-1[5] Cl 9.3.2.2, this allowance is the lesser of 500 mm or h

b/10.

In the usage chart, design checks show how efficiently the selected data are working. Design status is shown at cell I36.

GEODesign!GEODesign! considers sliding, overturning about the toe (toppling) and bearing pressures for Combination 1 and Combination 2. Again formulae for each action, moment and parameter are shown at the right hand side of the sheet. The relevant partial factors are not shown in these formulae but are used in the appropriate cells.

In terms of sliding, the undrained resistance is ignored if cohesion for the foundation material specified at DATA!H36 is less than 10 kN/m2. In this case it is recommended that the allowance of passive pressure at DATA!L16 is switched off.

RCDesign!The wall stem, base, heel and shear key are in turn designed and checked for flexure, shear, and bar spacing. For the concrete section Combination 1 is critical. In addition a span/depth deflection check is made on the stem.

Weight!Weight gives the approximate weight of reinforcement required per metre length of wall. Simplified curtailment rules are used. The figures should be regarded as estimates as the spreadsheet cannot deal with designers and detailers preferences, rationalisation, steps, changes in levels or direction etc.

Ref!Ref! Defines the values of various parameters used in the spreadsheet. These include NPDs according to Eurocode 2 and the partial factors for Combination 1 and Combination 2 according to the UK National Annex to Eurocode 7. Details of compaction plant loads and basic formulae are given.

Notes!This sheet gives disclaimers and revision history.

17

* Guidance on typical soil densities, angles of shearing resistance and surcharge loadings is given Guide to the Design and Construction of Concrete Basements[7]

TCC62 Retaining Wall / DATA!

18

TCC62 Retaining Wall.xls

TCC62 Retaining Wall / GEODesign!

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TCC62 Retaining Wall / RCDesign!

20

TCC63 Core Wall Design.xls

TCC63.xls determines the distribution of lateral moments between simple core walls and then finds the amount of reinforcement required. The program will accept a maximum of four cores. Input is required over two pages.

GEOMETRY!This single sheet contains of all of the inputs for basic building plan geometry and core dimensions. Most inputs, which are in blue and underlined, should be self-explanatory. The legend diagram at the top of the sheet defines the geometry input parameters, and the active diagram below serves as a visual check on the input of core dimension data.

After determining the section data for each core, percentages of lateral moment to each core and in each orthogonal direction are displayed. These include the effects of in-plane torsion due to the eccentricities of the cores from the centre of the structure.

CORE!On this sheet the total characteristic lateral moments in each direction are input, then after selecting one of the cores, the local coordinates and characteristic values of up to eight vertical loads are entered. After selecting the type of building usage, six ULS combinations are calculated and stresses (both compressive and tensile) and required reinforcement are produced for up to eight locations within the core. Again, there is an active diagram as a visual check on the input of vertical loads.

Gra!This page contains only data used in generating the various charts.

Ref!Ref! Defines the values of various parameters used in the spreadsheet. These include NPDs according toEurocode 2 and the c values from Table A 1.1 of BSEN 1990.

Notes!This sheet gives disclaimers and revision history.

21

TCC63 Core Wall Design.xls

TCC63 Core Wall Design / GEOMETRY!

22

TCC63 Core Wall Design.xls

TCC63 Core Wall Design / CORE!

23

This spreadsheet designs restrained two-way solid slabs in accordance with Eurocode 2. Moment and shear factors have been taken from Tables 3.14 and 3.15 of BS 8110: Part 1 (these yield-line factors are equally valid for use with EC2). Input is required on the first two sheets.

MAIN! This single sheet consists of the input and main output. In itself it should prove adequate for the design of restrained two-way slabs. Inputs are underlined and most should be self-explanatory. Self-weight, moment and shear factors are calculated automatically. The use of these factors is limited by the conditions for which they were produced, i.e. similar loads on adjacent spans and similar spans adjacent. Where these relevant conditions are not met, users should consider alternative methods of analysis. Whilst ultimate reactions to beams are given, shear per se is not checked as it is very rarely critical. The dimension l

y must be greater than l

x : bays where l

x

ly are invalid. It is recognised that B

1 can be parallel

to ly and the user should specify in which layers the

top and bottom reinforcement are located (see cells D33 and H33). In line 32 the user is asked to specify the diameters of reinforcement to be used. This reinforcement should be provided at the required centres in accordance with BS 8110 Clause 3.5.3.5 (1) to (7) (middle strips and column strips, torsion reinforcement at corners where an edge or edges is/are discontinuous). The spreadsheet highlights whether additional reinforcement for torsion is required or not. As noted under Deflection, the area of steel required, A

sreq, may be automatically increased in order to

reduce service stress, ss, and increase modification

factors to satisfy deflection criteria. An approximate reinforcement density is given. This is approximate only and excludes supporting beams, trimming to holes, etc.

WEIGHT! Weight! gives an estimate of the amount of reinforcement required in a slab. Simplified curtailment rules are used to determine lengths of bars. The figures should be treated as approximate estimates only as they cannot deal with the effects of designers and detailers preferences, rationalisation, the effects of holes, etc. To the right of the sheet are calculations of bar length, etc. Support widths are required as input as they affect curtailments and lengths.

Refs! This sheet comprises the values for nationally determined parameters that have been used in the spreadsheet. These data reflect the values given in the UK National Annexes for EN 1990 and EN 1992.

Notes! This sheet gives disclaimers and revision history.

24

TCC94 Two-way slabs (Tables).xls

TCC94 Two-way Slabs (Tables).xls

TCC94 Two-way slabs (Tables).xls / MAIN!

25

TCC94 Two-way slabs (Tables).xls / Weight!

26

TCC94 Two-way Slabs (Tables).xls

27

References

1 GOODCHILD C H & WEBSTER R M User Guide to RC Spreadsheets: v3, CCIP-008. The Concrete Centre, 2006.

2 BRITISH STANDARDS INSTITUTION. BS EN 1992 1-1, Eurocode 2 Part 1-1: Design of concrete structures General rules and rules for buildings. BSI, 2004. Including National Annex to BS EN 1992-1-1, Eurocode 2 Part 1-1: Design of concrete structures General rules and rules for buildings 2005 incorporating National Amendment No 1, BSI, 2009.

3 BRITISH STANDARDS INSTITUTION. BS 8110: 1997 Structural use of concrete. Part 1. Code of practice for design and construction. British Standards Institution, London, 1997 up to and including Amendment 4.

4 GOODCHILD C H & WEBSTER R M User Guide to RC Spreadsheets: v2, The Concrete Centre, Published electronically based on GOODCHILD C H & WEBSTER R M User Guide to RC Spreadsheets. British Cement Association on behalf of the Reinforced Concrete Council

5 BRITISH STANDARDS INSTITUTION. BS EN 1997-1, Eurocode 7 Geotechnical design Part 1: General rules. BSI, 2004 Including National Annex to BS EN 1997-1, Eurocode 7 Geotechnical design

6 BROOKER, O. et al. How to design concrete structures using Eurocode 2 (compendium), CCIP 006. The Concrete Centre, 2006.

7 NARAYANAN, R S & GOODCHILD, C H, Guide to the Design and Construction of Concrete Basements, TCC CCIP-044, Due 2010

8 MACLEOD, I.A. ET AL. Information technology for the structural engineer. The Structural Engineer, Vol. 77, No. 3, 2 February 1999. pp. 23 - 25.

9 STANDING COMMITTEE ON STRUCTURAL SAFETY, Standing Committee on Structural Safety, 10th Report, July 1992-June 1994, SETO Ltd, London, 1994 pp. 32

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The Advisory Group Members

S AlexanderS AlhayderiDr H Al-QuarraI BaldwinC BarkerM BeamishA BeasleyT BedfordG BeltonR BhattR BickertonP BlackmoreD BlackwoodM BradyC BuczkowskiA CampbellDr P ChanaG CharlesworthL ChengMr ChichgerR CollisonA CraddockM MortonJ CurryJ Dale

H DikmeC P EdmondsonJ ElliotI FelthamG FernandoM FernandoI FrancisA FungP GardnerJ GayP GreenA HallN HarrisG HillD W HobbsR HulseM HutchesonA IdrusN ImmsP JenningsD KennedyG KennedyR JothirajDr S KhanA King

G KingS KingK KusI LockhartM LordB LorimerM LovellDr LukerJ LuptonM LytridesProf I MacleodF MalekpourA McAtearA McFarlaneF MohammadA MoleM MortonR MossB MuntonC OBoyleDr A OkorieT ONeillB Osafa-KwaakoD PatelD Penman

M PereraB QuickY RaqifA RathboneM RawlinsonP ReynoldsH RileyN RussellU P SarkiT SchollarA StalkerA StarrM StevensonB StokerB TreadwellA TrubyR TurnerT VineyDr P WalkerB WatsonJ WhitworthC WilbyS WildeA WongE Yarimer

CCIP 053

Published August 2010

MPA - The Concrete Centre

Riverside House, 4 Meadows Business Park,

Station Approach, Blackwater, Camberley, Surrey, GU17 9AB

Tel: +44 (0)1276 606800 Fax: +44 (0)1276 606801

www.concretecentre.com

User Guide to RC Spreadsheets: v4 (Addendum to v3)

This update to the user guide provides guidance on the use of RC Spreadsheets v4 for the design of reinforced concrete elements.

The release of version 4 of the spreadsheets and user guide follows revision of The Concrete Centre series in line with amendment AMD 1 of the UK National Annex to Eurocode 2 . The RCC series of spreadsheets remain suitable for design calculations to the BS 8110 (up to and including Amendment 4), which was withdrawn in early 2010.

For more information on the spreadsheets visit www.concretecentre.com/rcspreadsheets

Charles Goodchild is Principal Structural Engineerfor The Concrete Centre where he promotes efficient concrete design and construction. He was responsible for the concept, content and management of this publication and of the RC Spreadsheets.

Rod Webster of Concrete Innovation & Design is principal author of the spreadsheets. He has been writing spreadsheets since 1984 and is expert in the design of tall concrete buildings and in advanced analytical methods.