Integrated Design Project Model Building Report – Techni Consultants

2

Table of Contents

1. Introduction .................................................................................................................................... 2

2. Evaluation of Drawings .................................................................................................................... 3 2.1. Timeliness ............................................................................................................................................. 3

2.1.1. Initial Drawings.......................................................................................................................................... 3 2.1.2. Requests for Information (RFI) .................................................................................................................. 3

2.2. Quality of Drawings ............................................................................................................................... 3 2.2.1. Initial Drawings.......................................................................................................................................... 3 2.2.2. RFI Response ............................................................................................................................................. 3

2.3. Buildability ............................................................................................................................................ 4

3. Model Building ................................................................................................................................ 4 3.1. Structure Selection ................................................................................................................................ 4 3.2. Construction Process ............................................................................................................................. 5

3.2.1. Methodology ............................................................................................................................................. 5 3.2.2. Material Selection ..................................................................................................................................... 5

3.3. Design Simplifications ........................................................................................................................... 5 3.4. Supplementary Modelling ..................................................................................................................... 6

3.4.1. Box Girder Decking .................................................................................................................................... 6 3.4.2. Cable Anchor Connection.......................................................................................................................... 6

4. Model Evaluation ...................................................................................................................................... 6

5. Table of Scaling ................................................................................................................................ 7

6. Request for Information .................................................................................................................. 8

7. Risk Assessment ............................................................................................................................ 10

1. Introduction One of Techni Consultants’ frequent clients is keen to test the accuracy and clarity of drawings produced by another consultant, prior to issuing these drawings for tender. Due to our large knowledge base and expertise, Techni, as a third party, has been asked to assess these drawings and produce models as a marketing tool to attract businesses to the completed project. Within this report, an evaluation of the drawings provided to Techni, as well as an outline of the model construction process and methodology, is presented. The report contains photographs and CAD drawings to illustrate the analysis undertaken, and to justify the model’s credibility.

3

2. Evaluation of Drawings 2.1. Timeliness

2.1.1. Initial Drawings Group I were not prepared for the drawing handover on time, with only two of their team members being present at the model building workshop on Friday 27/05/16. This ultimately prevented work on our part, since we could not progress with analysis of either of their designs. Later that day, we received an AutoCAD file of their bridge superstructure, which was analysed by Techni members over the course of the weekend. This delay meant that we met on Monday 30/05/16, despite it being a bank holiday, to engineer a construction methodology, to plan for the model building stage. The concourse drawings were not received until Tuesday 31/05/16 – this didn’t prove a major issue since we understood beforehand, following discussion with Team I, that the complexity of this design made it unfeasible to effectively make a model with our resources. This is discussed in section 2.3.

2.1.2. Requests for Information (RFI) An RFI form was sent by Techni on Friday 27/05/16, following the aforementioned delay. It was sent to one team member of Team I who happened to be away for the extended weekend without access to internet (which we were not made aware of). This was an oversight on our part, and definitely a lesson learned. In future, we would always send it to more than one team member. However, it is worth noting that in most professional environments, such a situation would be resolved using an ‘out-of-office’ email reply. A response was received by noon on Tuesday 31/05/16. Due to the time constraints, a lot of our model design had already been undertaken – however, we worked in feedback wherever possible. This is outlined further in 2.2.2.

2.2. Quality of Drawings

2.2.1. Initial Drawings The drawings received were generally of a high quality. There was a good use of colour to distinguish between different structural members, and a variety of sectional views were provided. This allowed for a good initial understanding of the structural form. Lots of detailing was given for the connections and various dimensions (although some further dimensions were requested which had been omitted). The AutoCAD file we were provided with (from which we measured several dimensions) was not always consistent with the dimensions annotated on the drawings – this slightly reduced our confidence in the accuracy of the whole drawing in terms of the sections working together in three dimensions.

2.2.2. RFI Response Despite being late, the RFI response was of a good standard. To rectify the lateness issue, some of the information was sent within email messages as soon as the team leader had access to the information. This allowed changes to be made to our 2D CAD drawings in order to address some of the issues Techni found with their design (see RFI). The formal response followed later on. Some changes to their design needed adding – for example, the extension of the walkway around the central A-frame tower to allow a safe pedestrian route was added on Techni’s advice.

4

2.3. Buildability Both of the designs provided to us by Team I were very interesting in their form. However, this brought with it issues in terms of buildability. Although Techni always welcomes a challenge, the team decided that a model of the bridge would display the structural form much more effectively than the concrete shell structure which didn’t have many individual members. The concourse design can be seen below.

However, the bridge did have some issues: lots of detailing was provided, especially in terms of connections. When scaled down, these proved too complex to add to the full bridge model. The decking, which is curved in profile, was designed as a series of concrete slabs supported by a box girder with an inverted trapezoidal form. Firstly, when scaled down, the thicknesses involved could not be effectively represented on the main model. We also had a buildability issue (which may translate into the real world context) as to how the box girder would be formed into a vertically curved section. Building this up with two-dimensional parts proved far too complex given our time and resource constraints. A potential way to form this bridge even more accurately would be to 3D print it.

3. Model Building 3.1. Structure Selection

Due to both buildability, time constraints and technical expertise, Techni selected the bridge to model. It has been designed to have a very interesting structural form, with a curved decking, different support methods for both sides of the bridge, and a visually striking design.

5

3.2. Construction Process

3.2.1. Methodology To improve the accuracy of our model, the vast majority of the individual elements were formed using a laser cutter. This was with the exception of columns and cables which were cut from longer pieces of material with constant cross section. The wires used to represent the cables were scaled up. For the purposes of the model, they don’t act structurally, they needed a certain level of rigidity to not hang limp and look as shown in the design above. The decking was cut into shape, before being bent into its final shape. To do this, extra length was allowed from the dimension in plan view to allow for the curvature. The deck was constructed in two pieces for two reasons: firstly, the dimensions of material available did not permit one continuous deck length; secondly, it allowed the A-frame to fit through the deck despite its angular form. The wires, representing the cables in tension, were actually hooked into the connections, before being secured. This was as accurate a portrayal of the connections we could do at the scale we were working at.

3.2.2. Material Selection A list of materials used for model parts, as well as justifications for their selection, can be found below:

Deck 0.8mm Plywood Selected due to its flexibility – an issue we found was that the wood is isotropic, causing an issue when it had to be bent in one direction.

Columns 3mm Square Balsa Wood

Available in square sections.

Connections 0.8mm Plywood Thin board required for sufficient level of detail to be demonstrated on scale used.

Cables 0.9mm Piano Wire Smallest size available which is rigid enough to hold straight line, seeming like it’s in tension.

Base Board 6mm Plywood Can be laser cut to allow layout to be cut into the top layered 6mm board. Also allows etching of detailing for final presentation.

3.3. Design Simplifications The main design simplification made for the modelling of the bridge was in the representation of the deck.

Techni opted for a uniform thickness span – this allowed flexibility for bending the wood, and at the scale used the thickness also roughly accurate. However, it does omit the detailing of the box girder. This is shown instead as a separate unit on a larger scale, mounted on the same model base board – see 3.4.1.

The connections specified were simplified significantly and enlarged slightly for use in the main model. This was a scaling issue as the actual connections would have been too small to build to show any level of detail. One of the connections has been shown in an expanded view, again mounted on the same base board. The scaling was so severe due to the extremely long span of the bridge, compared to normal small river-spanning bridges.

The cable diameters were assumed to be the same, since at a 1:250 scale sufficiently different wires representing the cables were not available.

The model focuses mainly on the visible parts of the structure. Hence, foundation designs were omitted.

6

3.4. Supplementary Modelling

3.4.1. Box Girder Decking The trapezoidal box girder decking couldn’t be constructed to a curve using using the materials and resources available. Therefore, to show this detail, a section of the decking has been added to the model on a larger scale. The deck, which can be seen in the background, was represented as a single depth, not including the girder. Here, the supplementary model was used to give detail to a simplification, mentioned earlier.

3.4.2. Cable Anchor Connection The cable anchors were included on the 1:250 scale model – however, to fully show their detailing, an expanded three-dimensional model of the anchor connections at 1:50 was included. In the photo (right) the two differently scaled versions of the same connection can be seen for a direct comparison. The simplification in the smaller connection is clear when seen next to the larger version.

4. Model Evaluation The final model is one of the most visually striking created in the IDP. The scale used makes the model look delicate and elegant, but gives us enough scope to have connection detailing. The blown up connection / section effectively convey the information required, whilst not detracting from the main model section.

7

5. Table of Scaling

Dimension Length on Model(mm)

Scale Representative Length (m)

Actual Length (m)

Percentage Error (%)

Height of deck from ground.

29 1:250 7.25 6.7 7.5

Height of tower

150 1:250 37.5 37.1 1.1

Span 540 1:250 135 140 3.7

Width of deck (main model)

48 1:250 12 12 0

Width of deck (deck section)

92 1:130 11.96 12 0.3

Height of connection detail

34 1:50 1.7 1.7 0

Length of base plate on connection detail

64 1:50 3.2 3.2 0

The accuracy of the model’s dimensioning is almost perfect where it is only dependent on the laser cutter. Where the accuracy does dip slightly, this is due to human error in the difficult task of bending the bridge deck to match its curvature in the AutoCAD drawing. All things considered, a maximum error of 7.5% seems acceptable.

8

6. Request for Information Project Title: IDP Part 2 Model Building Group J Issue date 27 / 05 / 2016 Project No. 2

REQUEST FOR INFORMATION RFI No. 1

Issued by: Group J Date reply required: 30 / 05 / 2016 09:00 Issued to: Group I Reply: acceptable Not acceptable Description of Query / Information Required: The following list outlines simple supplementary information we feel is needed to accurately capture your design in model form. We would appreciate any dimensions to be added to the AutoCAD file with which we were provided and re-sent to us as soon as is possible, and by the specified date at the latest. 1. The spacing of the columns under the bridge 2. The height of the columns under the bridge / deck level at these points 3. Regarding the cables supporting the deck, clarification of cable diameters for each cable (currently 3 different

cables are specified and the rest without dimensions) 4. The length of the deck 5. The widths of the central column, which the cables are tied to 6. Clearance above the river Don 7. Any isometric/GSA drawings you have of the bridge if any were created in the detailed design stage, to give a

three-dimensional contextualisation against which we can judge the model 8. A diagram showing the bridge’s location relative to the rest of the site lauout We also have a query regarding the central column of your bridge – in the ‘front view’ drawing, it is clear the tram’s kinematic envelope has been allowed for, but what happens to the pedestrian route at this point? There is 2m width allowed for the rest of the bridge, but only a very narrow passage around the columns at the central point. If this is a design oversight and you want to alter the design, please make these changes as soon as possible. Secondly, are there any handrails / barriers planned on the edges of the bridge/in between the pedestrian route and the trams? If not, is this something you would like to add to the model or not? Finally, we would also like your input on the aesthetics of the bridge model – for example any colour / landscaping choices you outlined in your detailed design report of which we should be aware beyond the pure structural assembly.

Name: James Featherstone Signature: JFeatherstone

9

Reply / Information: Thanks for the request. The requested dimensions are stated as follow:

The walkway where the columns intrude upon the pedestrian route was planned to be widened. This isn't dimensioned, and was left out of the drawings, but the idea is a semi-circular additional path to keep a 2 metre clearance.

There should be pedestrian rails. If the steel is painted it should be a fairly neutral colour. The idea I suppose is to underline the structural

form of the bridge itself and not detract from that. The cable thicknesses are in groups of 3 on that side, of the thicknesses stated. again our mistake Central column is 1.2m wide hollow section with thickness of 300mm. Column spacing is at 5m centres. The heights of the columns from left to right are 6.94m, 6.74m, 6.41m, 5.96m, 5.37m, 4.65m, 3.79m, 2.8m,

1.9m, 1.28m and 0.68m. The total bridge span is 140m The files you requested have been sent, contact us at once if you have not received yet.

That would be all the information you requested. If there any more queries, please contact us via email and the email is jhook1@sheffield.ac.uk. Name: Tak Pui Sit Signature: Tak Pui Sit Date: 31 / 05 / 2016

7. Risk Assessment This has been signed on the hard copy of this report, submitted with the model.

Risk Assessment Form for Model Making

PERSONS AT RISK : Students Reference No: CIV3203 - Integrated Design Project (MEng Students only)

Risk: (L) Low Environment: WR1 & WR4 (internal area)

TASK or ACTIVITY: Model Making from 20/5/2013 - 24/5/2013 INITIAL FINAL

RISK RISK

SIGNIFICANT HAZARD RISK RATING EXISTING CONTROL/PROPOSED CONTROL MEASURES RATING

Model making knife Cuts, bleeding M 1. Ensure blade is securely attached to the handle before using. L

2. Always place material to be cut on a rigid cutting board or surface.

3. Always cut away from you.

4. Use a safety rule when forming a straight cut.

5. Do not apply excess pressure to the blade.

6. Keep protective cap on blade when not in use.

7. Never leave knives unattended.

Glue, including glue guns Eye contact M 1. Read manufacturers's instructions before using glue or adhesives. L

Skin contact 2. Read separate 'Glue Gun' guidance sheet before using glue guns.

Inhalation 3. Work strictly in accordance with manufacturer's instructions and 'Glue Gun'

guidance sheet at all times.

4. Avoid contact with nozzle of glue gun, or molten glue.

5. Rinse eye thoroughly with clean water after contact with cold glue/adhesive.

6. Rinse eye with copious amounts of clean water after contact with hot glue

or adhesive, and then seek medical advice.

7. Put cap back on glue/adhesive immediately after use.

8. Put glue gun on stand, and turn off, after use.

9. Wear (latex free) gloves if using 'Super Glue', or as instructed.

10. Open windows and sit down if feeling faint or nauseous.

For first aid, contact either Paul Bentley on extension 25708/room F111D or Jonathan Black on extension 25110/room D108. Overall Risk: L

Risk Assessment undertaken by: Jon Carr on 17/5/2013 Other Persons Consulted: Rachel Horn & Glenn Brawn

I hereby confirm that I have read and understood this risk assessment sheet;

Name: Group: Date:

Name: Group: Date:

Name: Group: Date:

Name: Group: Date:

Name: Group: Date:

Name: Group: Date:

The University of Sheffield

11

CIV 3203 Integrated Design Project: MEng Part 2 – Model Making: Assessment of Performance Levels

Group carrying out the Assessment: Group J Date: 02/06/2016

Group whose drawings you are assessing (Group I)

Group whose model and report you are assessing (Group K)

Assessment Criteria Unsatisfactory

< 40%

Satisfactory 40% – 50%

Good 50% – 60%

Very Good 60% – 70%

Excellent 70% – 80%

Exceptional > 80%

Clarity, accuracy and timeliness of information

provided (Group I)

Th

resh

old

60%. Drawings were of a high quality, however, we only received the drawings for one superstructure and lateness caused us to lose a working day.

Fir

st

Buildability of design (Group I)

Th

resh

old

65%. Modelling the bridge structure posed some difficulties, however, the information provided proved to be enough to create a good model. F

irst

Interpretation and quality of construction (Group K)

Th

resh

old

70%. Accurate representation of drawings with only some variations in design. Some slight inaccuracies, especially regarding the embankments.

Fir

st

Quality of evaluation in ‘review report’ (Group K)

Th

resh

old

Fir

st

72%. Excellent report covering all the relevant

criteria.