Design Rep Slab Bridges T D (230799)

DESIGN REPORT OF RCC SLAB BRIDGES ON TOPI DARBAND ROAD

INTRODUCTION

This document details the design criteria, parameters adopted and designed sections for bridges on the Topi Darband Road. The bridges are situated:

At Km 7 + 072,At Km 9 + 725,At Km 10 + 615,At Km 63 + 200,

& At Km 64 + 807,

Detail drawings are separately submitted.

PART – I GENERAL INFORMATION

1.0 DESIGN SPECIFICATION

1.1 AASHTO LRFD code 1994 (BRIDGE DESIGN SPECIFICATIONS)

1.2 AASHTO Standard specifications 1996.

1.3 Pakistan Code of Practice for Highway Bridges (PCPHB) 1967.

2.0 DESIGN PHILOSOPHY (Limit states, of AASHTO LRFD 1994)

2.1 Service limit state (stability check of the abutments).

2.2 Strength limit state (Design of all the structural components).

3.0 LIVE LOADS

3.1 Single Lane of Military Class 70 Loading (PCPHB, 1967.).

3.2 Two lanes of Class A Loading (PCPHB).

3.3 HS20-44 Truck (AASHTO standard 1996).

3.4 Design Lane Load plus Design Truck (HL – 93, AASHTO LRFD 1994).

3.5 Design Lane Load plus Design Tandem (HL – 93, AASHTO LRFD 1994).

C2\535\91007\150\150\Design Rep-T-Girders-T-D-(160799).doc

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4.0 MATERIAL PROPERTIES

4.1 Concrete used in the slab, Class A concrete of 28 daysand footings. Curbs, railings, back walls, wing walls,

cylinder compressive strength of210 kg/cm2 (21 MPa.).

4.2 Primary Reinforcement steel Grade 60 (414 MPa) deformed roundbars confirming to ASTM A-615

4.3 Secondary Reinforcement steel Grade 40 (276 Mpa) deformed round bars conforming to ASTM A-615.

4.4 Modulus of elasticity of reinforcing steel Es = 200,000 MPa.

4.4 Modulus of elasticity of concrete Ec = 4800* MPa.

5.0 DESIGN PARAMETERS. (Ref: ASSHTO LRFD)

5.1 Resistance factors, , are:

5.1.1 Flexure and tension of reinforced concrete =0.905.1.2 Shear and torsion in normal density concrete = 0.905.1.3 Axial compression with spirals and ties = 0.755.1.4 Bearing on concrete = 0.70

5.2 Load combinations and Load factors : Following limit states are investigated.

5.2.1 Service – l Limit state 5.2.2 Strenght – l Limit State

PART – II PARTICULAR INFORMATION


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A. RCC SLAB BRIDGE AT KM 7 + 072

1.0 HYDROLOGICAL INFORMATION (Ref: AASHTO LRFD)

1.1 Catchment area = 6.59 Km2

1.2 Intensity of the rainfall i = 46.08 mm/hr

1.3 Coefficient of run off C = 0.5

1.4 Discharge (100 years) Q = 54.48 m3/sec

2.0 GEOTECHNICAL INFORMATION

2.1 Unit weight of the granular backfill (soil) soil = 18000 N/m3

2.2 Angle of internal friction of the granular backfill = 35

2.3 Recommended value to be used for the general geology anticipated at the bridge site (Weathered or broken rock of any kind; shale etc.) = 0.479MPa

3.0 SUPER STRUCTURE

3.1 General Information About Bridge Geometry (Ref: AASHTO LRFD)

3.1.1 No. of Spans = 1

3.1.2 Each Span Length = 8.3 meters.

3.1.3 Total Span Length = 8.3 meters.

3.1.4 Effective Span Length = 7.8 meters.

3.1.5 Skew Angle = 0

3.1.6 Type of Superstructure RCC Deck Slab.

3.1.7 Clear Width of the Bridge = 7300 mm

3.1.8 Total Width of the Bridge = 9050 mm

3.1.9 Type of guardrail R.C.C. wall type Guard Rail

3.2 Dynamic load allowance (not applied to the design lane load) are:

3.2.1 For HL – 93, Loading Truck and Tandem IM = 33 %3.2.2 For all other loadings IM = 30 %

Rational formula for discharges (Hydrology in Practice by Elizabeth M. Shaw pp/297).


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3.3 DESIGN OF DECK SLAB (Ref: AASHTO LRFD)

3.3.1 Minimum depth of the deck slab = 452 mm.(Sec. 9.7.1.1, AASHTO LRFD 1994)

3.3.2 Thickness of the deck slab = 600 mm.

3.3.3 Primary Reinforcement steel used Grade 60 steel (ASTM A – 615)

3.3.4 Secondary Reinforcement steel used Grade 40 steel (ASTM A – 615) (Distribution and shrinkage steel)

3.3.5 Ultimate positive moment = 274197.7 N – m.

3.3.6 Ultimate positive moment resisting capacity of Md(+ve) = 462310.8 N – m.the deck slab

3.3.7 Ratio of positive moment capacity to ultimate applied = 1.68positive moment

4.0 SUB – STRUCTURE DESIGN

4.1 General Information

4.1.1 Type of abutment CRM Abutment.

4.1.2 Width of the CRM wall at top = 825 mm.

4.1.3 Width of the CRM wall at bottom = 4000 mm.

4.1.4 Length of the CRM wall (Transverse to the Traffic direction) = 9050 mm.

4.1.5 Height of the CRM wall = 7250 mm.

4.1.6 Total Height of abutment = 8750 mm.(from bottom of the footing to the deck Level)

4.1.7 Type of footing RCC Spread footing

4.1.8 Width of footing = 5.50 meters.

4.1.9 Length of footing = 11.05 meters.

4.1.10 Depth of footing = 500 mm.

4.2 Stability Analysis Of The Abutments

4.2.1 Weight of the structure (including weight of the footing and backfill) on the footing =7.43 X 106 N


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4.2.2 Total stabilizing force (weight of footing is not included) = 6.8 X 106 N

4.2.3 Total stabilizing moment about toe of the CRM wall = 18.6X 106 N – m.

4.2.4 Total sliding force = 1.96 X 106 N.

4.2.5 Total overturning moment about toe of the CRM wall = 6.82 X 106 N – m.

4.2.6 Coefficient of friction between the CRM wall and footing = 0.5

4.2.7 Factor of safety against sliding (F.O.S.)sliding = 1.72

4.2.8 Factor of safety against overturning (F.O.S.) over turning. = 2.73

4.3 Pressure Distribution At Base Of The Footing

4.3.1 Stresses at toe of the footing qmax = - 0..07 MPa.

4.3.2 Stresses at heel of the footing qmin = - 0.19 MPa.

4.3.3 Presumptive allowable bearing capacity = 0.77 To 1.1 MPa.(Ref: AASHTO LRFD)

4.3.4 Recommended value of use = 0.96 MPa.(Weathered or broken rock of any kind; shale etc.)


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PRESSURE DISTRIBUTION DIAGRAM FOR THE ABUTMENT FOOTING

4.4 Structural Design Of Sub – Structure Ancillary Elements


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4.4.1 Design Of Girder Seat/Transom

4.4.1.1 Width of the transom = 825 mm.

4.4.1.2 Depth of the transom = 400 mm.

4.4.1.3 Effective depth of the transom = 340 mm.

4.4.1.4 Minimum area of steel = 1400 mm2.

4.4.1.5 Moment of inertia of the transom I = 0.4x1010 mm4.

4.4.1.6 Modulus of elasticity of the transom concrete E = 149.47 MPa.

4.4.1.7 Flexural rigidity of the transom EI = 5.97x1011 N-mm2

4.4.1.8 Reinforcement steel 20 8 bars uniformlydistributed.

Note: The transom is provided as a rigid element to distribute the load of super structure at top of the abutment wall (CRM wall). Its flexural rigidity is more than sufficient to distribute the load uniformly over the abutment and to take care for any localized differential settlement in CRM wall.

4.5 DESIGN OF BACKWALL

4.5.1 Thickness of the Backwall = 250 mm.

4.5.2 Effective depth of the backwall = 195 mm.

4.5.3 Ultimate moment at base of the Backwall = 2000 N – m/m

4.5.4 Minimum area of steel = 500 mm2/m

4.5.5 Moment capacity of the section = 4530 KN – m/m.

4.5.6 Ratio of ultimate moment capacity and ultimate applied moment = 2.26

4.5.7 Main reinforcement steel 6 @ 150 mm c/c. (B.F.)

4.5.8 Shrinkage steel 6 @ 150 mm c/c. (B.F.)

4.5.9 Ultimate shear at base of the Backwall = 6960 N.

4.5.10 Ultimate shear capacity of the backwall = 133000 N.

4.5.11 Ratio of the ultimate shear capacity to = 19.23ultimate applied shear

4.6 DESIGN OF THE ABUTMENT FOOTING


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4.6.1 Width of the footing = 5500 mm.

4.6.2 Length of the footing = 11050 mm.

4.6.3 Depth of the footing = 500 mm.

4.6.4 Clear cover for the flexural steel = 75 mm.

4.6.5 Effective depth of the footing = 425 mm.

4.6.6 Applied punching shear on the footing = 6380000 N.

4.6.7 Punching shear capacity of the footing = 14638000N.

4.6.8 Ratio of the punching shear capacity = 2.29to applied punching shear

4.6.9 Applied beam shear = 1082000 N.

4.6.10 Beam shear capacity of the footing = 3116000 N.

4.6.11 Ratio of the beam shear capacity to the = 2.88applied beam shear

4.6.12 Ultimate moment, in shorter direction, Mu1 = 82000.2 N-m/m.at face of the support

4.6.13 Reinforcement steel provided in shorter direction (As-mini) 20 @ 300 mm c/c.

4.6.14 Ultimate moment capacity in shorter direction Md1 = 105000.7 N–m/m.

4.6.15 Ratio of the ultimate moment capacity to ultimateapplied moment In shorter direction = 1.28

B. RCC SLAB BRIDGE AT KM 63+200

1.0 HYDROLOGICAL INFORMATION (REF: AASHTO LRFD)

1.1 Catchment area Acatch = 2.79 Km2.

1.2 Intensity of the rain fall i = 91.08 mm/hr.


1.4 Discharge (100 years) Q = 45.38 m3/sec.

Rational formula for discharges (Hydrology in Practice by Elezabeth M. Shaw pp/297).


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2.1 Unit weight of the granular backfill (soil) soil = 17300 N/m3.


2.3 Recommended value to be used for the = 0.479 MPa.general geology anticipated at the bridge site.(Gravel, gravel-sand mixture, boulder-gravel mixtures)

3.0 SUPER STRUCTURE

3.1 SAME AS BRIDGE AT 7+072


4.1 GENERAL INFORMATION




4.1.4 Length of the CRM wall = 9050 mm.(Transverse to the Traffic direction)



4.1.7 Type of footing R.C.C. Spread footing.




4.2 STABILITY ANALYSIS OF THE ABUTMENTS.


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1.2.11.2.1 Weight of the structure = 4.24 X 106 N.(including weight of the footing and backfill)

4.2.2 Total stabilizing force = 3.73 X 106 N.(weight of footing is not included)

4.2.3 Total stabilizing moment about toe of the CRM wall = 7.72 X 106 N – m.

4.2.4 Total sliding force = 0.9X 106 N.




4.2.8 Factor of safety against overturning (F.O.S.) over turning.= 3.41

4.3 PRESSURE DISTRIBUTION AT BASE OF THE FOOTING.

4.3.1 Stresses at toe of the footing qmax = - 0.08 MPa.

4.3.2 Stresses at heel of the footing qmin = - 0.12 MPa.

4.3.3 Presumptive allowable bearing capacity = 0.77 To 1.1 MPa.(Ref: AASHTO LRFD)

4.3.4 Recommended value of use = 0.96 MPa. (Weathered or broken rock of any kind; shale etc.)


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5 STRUCTURAL DESIGN OF SUB – STRUCTURE ANCILLARY ELEMENTS

5.1 DESIGN OF GIRDER SEAT/TRANSOM

5.1.1 Width of the transom = 825 mm.

5.1.2 Depth of the transom = 400 mm.

5.1.3 Effective depth of the transom = 340 mm.

5.1.4 Minimum area of steel = 1400 mm2.

5.1.5 Moment of inertia of the transom = 0.4x1010 mm4.

5.1.6 Modulus of elasticity of the transom concrete E =149.47 MPa.

5.1.7 Flexural rigidity of the transom EI = 5.97x1011 N-mm2

5.1.8 Reinforcement steel 20 8 bars uniformly distributed.



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5.2.3 Ultimate moment at base of the Backwall Mu = 2000 N – m/m


5.2.5 Moment capacity of the section = 10000 N – m/m.

5.2.6 Ratio of ultimate moment capacity and ultimate applied moment = 5.11





5.2.11 Ratio of the ultimate shear capacity to ultimate applied shear = 19.2




5.3.3 Depth of the footing = 500 mm




5.3.7 Punching shear capacity of the footing = 12041000N.


5.3.9 Beam shear capacity of the footing = 3116000 N

5.3.10 Ratio of the beam shear capacity to the applied beam shear = 4.5



5.3.13 Ultimate moment capacity in shorter direction Md1 = 263000.5 N–m/m

5.3.14 Ratio of the ultimate moment capacity to ultimat applied moment In shorter direction = 5.0


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C. RCC SLAB BRIDGE AT KM 64+807


1.1 Catchment area Acatch = 1.05 Km2.







2.3 Recommended value to be used for the general = 0.479 MPa.geology anticipated at the left abutment of the bridge(Weathered or broken rocks)

3.0 SUPER STRUCTURE

3.1 SAME AS BRIDGE AT 7+072

3.2 Dynamic load allowance (not applied to the design lane load)are:

3.2.1 For HL – 93, Loading IM = 33 %Truck and Tandem

3.2.2 For all other loadings IM = 30 %










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4.2.1 Weight of the structure = 7.5 X106Nincluding weight of the footing and backfill) on the footing

4.2.2 Total stabilizing force(weight of footing is not included) = 6.85 X 106 N.




4.2.6 Coefficient of friction betweenthe CRM wall and footing = 0.5

4.2.7 Factor of safety against overturning F.O.S.) over turning. = 2.74 .


4.6.16 Stresses at toe of the footing qmax = - 0.08 MPa

4.6.17 Stresses at heel of the footing qmin = - 0.19 MPa

4.6.18 Presumptive allowable bearing capacity(Ref: AASHTO LRFD) = 0.77 To 1.1 MPa.

4.6.19 Recommended value of use(Weathered or broken rock of any kind; shale etc.) = 0.96 MPa.


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Based on the design experience of our Bridge Engineer it is suggested that the existing abutments of the bridge are safe and sound and shall not be replaced with new abutments.

.


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5.0 STRUCTURAL DESIGN OF SUB – STRUCTURE ANCILLARY ELEMENTS





5.1.4 Minimum area of steel = 1400 mm2

5.1.5 Moment of inertia of the transom I = 1.755x1010 mm4.

5.1.6 Modulus of elasticity of the transom concrete E = 149.47 MPa.

5.1.7 Flexural rigidity of the transom EI =2623x1014 N-mm2



5.2DESIGN OF BACKWALL

5.2.1 Thickness of the Backwall ` = 250 mm.



5.2.4 Moment capacity of the section = 6860 KN – m/m

5.2.5 Ratio of ultimate moment capacity = 3.42and ultimate applied moment






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5.3DESIGN OF THE ABUTMENT FOOTING







5.3.7 Punching shear capacity of the footing = 14638000 N.

5.3.8 Ratio of the punching shear capacityto applied punching shear. = 2.28



5.3.11 Ratio of the beam shear capacityto the applied beam shear = 2.86



5.3.14 Ultimate moment capacity in shorter direction Md1 = 157000 N–m/m.

5.3.15 Ratio of the ultimate moment capacity to ultimate = 1.9applied moment In shorter direction

D. RCC SLAB BRIDGE AT KM 9+725


1.1 Catchment area Acatch = 4.18Km2.


The intensity of rain fall is assumed on the basis that the probability of rain fall over the whole area at the same time is low. Also the flood will take a longer time to reach the point of consideration. Therefore a lesser value of rain fall intensity is considered.


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2.3 Recommended value to be used for the general = 0.479 MPaat the geology anticipated left abutment of the bridge

(Weathered or broken rocks)

3.0 SUPER STRUTURE

3.1 GENERAL IFORMATIONS ABOUT BRIDGE GEOMETRY (Ref: AASHTO LRFD)

3.1.1 No. of Spans = 3

3.1.2 Each Span Length = 7 meters.

3.1.3 Total Span Length = 21 meters.




3.1.7 Clear Width of the Bridge = 7300 mm

3.1.8 Total Width of the Bridge = 9050 mm.

3.1.9 Type of guardrail R.C.C. wall type Guard Rail.


4.1 For HL – 93, Loading Truck and Tandem IM = 33%4.2 For all other loadings IM = 30 %



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4.1DESIGN OF DECK SLAB (Ref: AASHTO LRFD)

4.1.1 Minimum depth of the deck slab = 452 mm.

(Sec. 9.7.1.1, AASHTO LRFD 1994)



4.1.4 Secondary Reinforcement steel used Grade 40 steel (ASTM A – 615)(Distribution and shrinkage steel

4.1.5 Ultimate positive moment = 336410 N – m.

4.1.6 Ultimate negative moment = 231115.5 N – m.

4.1.7 Ultimate positive moment resisiting Md(+ve) = 874921.3 N – m.capacity of the deck slab

4.1.8 Ultimate negative moment resisting Md(-ve) = 874921.3 N – m.capacity of the deck slab

4.1.9 Ratio of positive moment capacity to = 2.6ultimate applied positive moment

4.1.10 Ratio of negative moment capacity to = 3.78ultimate applied negative moment

4.2SUB – STRUCTURE DESIGN

4.2.1 GENERAL INFORMATION






4.2.6 Total Height of abutment = 9750 mm(from bottom of the footing to the deck Level)



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4.3STABILITY ANALYSIS OF THE ABUTMENTS.

4.3.1 Weight of the structure = 8.91 X 106 N.(including weight of the footing and backfill)on the footing

4.3.2 Total stabilizing force (weight of footing is not included) = 8.00 X 106 N.

4.3.3 Total stabilizing moment about toe of the CRM wall = 24.32 X 106 N – m


4.3.5 Total overturning moment about toe of the CRM wall = 9.416 X 106 N – m




4.4PRESSURE DISTRIBUTION AT BASE OF THE FOOTING.

4.4.1 Stresses at toe of the footing qmax = - 0. 06MPa.4.4.2 Stresses at heel of the footing qmin = - 0. 19MPa.4.4.3 Presumptive allowable bearing capacity = 0.77 To 1.1 MPa.

(Ref: AASHTO LRFD) 4.4.4 Recommended value of use = 0.96 MPa.

(Weathered or broken rock of any kind; shale etc.)


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5.1.5 Moment of inertia of the transom I = 1.485x1010 mm4



5.1.8 Reinforcement steel 20 8 bars uniformly distributed


5.2DESIGN OF BACKWALL



5.2.3 Ultimate moment at base of the Backwall Mu = 1000.3 N – m/m


5.2.5 Moment capacity of the section = 4000.58 KN – m/m.

5.2.6 Ratio of ultimate moment capacity and = 3.38ultimate applied moment



5.2.9 Ultimate shear at base of the Backwall = 5000.61 N.

5.2.10 Ultimate shear capacity of the backwall = 133000.28 N.


5.3DESIGN OF THE ABUTMENT FOOTING







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5.3.8 Ratio of the punching shear capacity to = 2.39applied punching shear

5.3.9 Applied beam shear = 1641000.7 N.


5.3.11 Ratio of the beam shear capacity to = 2.44the applied beam shear

5.3.12 Ultimate moment, in shorter direction, Mu1 = 148000 N-m/m.at face of the support



5.3.15 Ratio of the ultimate moment capacity to ultimate =1.32applied moment In shorter direction

E. RCC SLAB BRIDGE AT KM 10+615


1.1 Catchment area Acatch

= 1.21Km2.1.2 Intensity of the rain fall i

= 78.33mm/hr.1.3 Coefficient of run off C = 0.51.4 Discharge (100 years) Q = 16.92 m3/sec.




2.3 Recommended value to be used for the general geology anticipated

at the left abutment of the bridge (Weathered or broken rocks) = 0.479 MPa.

The intensity of rain fall is assumed on the basis that the probability of rain fall over the whole area at the same time is low. Also the flood will take a longer time to reach the point of consideration. Therefore a lesser value of rain fall intensity is considered.



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3.0 SUPER STRUCTURE

3.1 GENERAL IFORMATIONS ABOUT BRIDGE GEOMETRY (Ref: AASHTO LRFD)

3.1.1 No. of Span = 3

3.1.2 Each Span Length = 6 meters.

3.1.3 Total Span Length = 18 meters.




3.1.7 Clear Width of the Bridge = 7300 mm.

3.1.8 Total Width of the Bridge = 9050 mm.

3.1.9 Type of guardrail R.C.C. wall type Guard Rail.


3.2.1 For HL – 93, Loading Truck and Tandem IM = 33 %3.2.2 For all other loadings IM = 30 %

3.3 DESIGN OF DECK SLAB (Ref: AASHTO LRFD)

3.3.1 Minimum depth of the deck slab

(Sec. 9.7.1.1, AASHTO LRFD 1994) = 300 mm.



3.3.4 Secondary Reinforcement steel used Grade 40 steel (ASTM A – 615)

(Distribution and shrinkage steel)

3.3.5 Ultimate positive moment = 306082.7 N – m.

3.3.6 Ultimate negative moment = 220991.8 N – m.

3.3.7 Ultimate positive moment resisiting capacity Md(+ve) = 639176.5 N – m.of the deck slab


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3.3.8 Ultimate negative moment resisting Md(-ve) = 639176.5 N – mcapacity of the deck slab

3.3.9 Ratio of positive moment capacity toultimate applied positive moment = 2.89

3.3.10 Ratio of negative moment capacity toultimate applied negative moment = 2.1








4.1.6 Total Height of abutment(from bottom of the footing to the deck Level) = 7900 mm.



4.1.9 Length of footing = 11.4 meters



4.2.1 Weight of the structure (including weight of the footing and backfill)on the footing = 5.04 X 106 N.

4.2.2 Total stabilizing force (weight of footing is not included) = 4.42 X 106 N.







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4.3.1 Stresses at toe of the footing qmax = - 0.21 MPa.

4.3.2 Stresses at heel of the footing qmin = - 0..01 MPa.

4.3.3 Presumptive allowable bearing capacity(Ref: AASHTO LRFD) = 0.77 To 1.1 MPa.

4.3.4 Recommended value of use = 0.96 MPa.(Weathered or broken rock of any kind; shale etc.)

RESSURE DISTRIBUTION DIAGRAM FOR THE ABUTMENT FOOTING


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Based on the design experience of our Bridge Engineer it is suggested that the existing abutments of the bridge are safe and sound and shall not be replaced with new abutments.

.







5.1.5 Moment of inertia of the transom I = 4.4x109 mm4.










5.2.5 Moment capacity of the section = 4580 N – m/m.

5.2.6 Ratio of ultimate moment capacity = 5.44and ultimate applied moment



5.2.9 Ultimate shear at base of the Backwall = 4000.33 N.

5.2.10 Ultimate shear capacity of the backwall = 133000.85 N.


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5.2.11 Ratio of the ultimate shearcapacity to ultimate applied shear = 30.88









5.3.8 Ratio of the punching shear capacity to applied punching shear = 1.82

5.3.9 Applied beam shear = 1122000.81 N.

5.3.10 Beam shear capacity of the footing = 4003000.2 N.

5.3.11 Ratio of the beam shear capacity

to the applied beam shear = 3.56

5.3.12 Ultimate moment, in shorter direction, at face of the support Mu1 = 117000.46 N-m/m

5.3.13 Reinforcement steel provided in shorter direction (As-mini) 20 @ 300 mm c/c


5.3.15 Ratio of the ultimate moment capacity to ultimate

applied moment In shorter direction = 1.12


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Documents

Design Rep Slab Bridges T D (230799)