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REPORT ON

INVESTIGATION AND DESIGN OF STRENGTHENING

OF

RED BRIDGE, CAMPBELL TOWN, TASMANIA

Gifford and Partners
Canton House
Ringwood Road
Woodlands
Southampton S040 7HT UK

  1.         INTRODUCTION

1.1    General

This report describes the investigation and design of strengthening for Red Bridge. It is the second of two reports concerned with the development of a strengthening and rehabilitation scheme using the Archtec technique. The work is part of a successful tender awarded as a design and construct contract and commissioned by the Department of Infrastructure, Energy and Resources(1). Geometric calculations for setting out and material schedules are not discussed but their results are included on the construction drawings.

As described in the first report(2) the evaluation of bridge strength has been based on numerical simulation using the discrete element (DE) technique. Simulations of the strengthened bridge including the retrofitted Cintec anchors has formed the major part of the design calculations. This technique is used exclusively by Gifford and Partners for the Archtec joint venture to accurately calculate masonry arch behaviour including strengthening.

The first report, concerned with the existing arch strength, concluded that the bridge was not capable of safely carrying live load in accordance with the Australian Bridge Design Code. It was recommended that strengthening using the Archtec technique is installed to extend the bridges capacity from the assessed existing strength to that required for current full live loading.

1.2    Existing Arch Strength Report

In the first report(2) the background, history and strategic importance of the bridge is briefly covered together with a full description of the existing structure. The principle bridge and carriageway dimensions were summarised together with the results of a site investigation to determine barrel and fill dimensions as well as to determine the strength of the masonry in the barrel.

The method of structural analysis and how this has been used to assess the bridges existing load carrying capacity is described. Two approaches were developed to determine the live load carrying capacity. The first approach used a numerical load test to determine the ultimate capacity of the bridge for a point load close to the critical loading position. The second method involved traversing live load across the bridge with incrementally increased load factors to determine the load intensity at failure. Using the results from these two approaches it was shown that at the ultimate limit state (ULS) full A160 axle loading exceeded the capacity of the bridge. Having identified a significant assessment failure with single axle loading further work on less critical multiple axle loading such as S1600 was found not to be necessary. Multiple axle load carrying capacity which is often critical to strengthened arches is addressed in Section 5.

1.3    Existing Arch Strength Assessment

A live load rating was calculated from the existing bridge strength assessment reported earlier(2). The overall assessment approach has been based on the UK Highways Agency Standard BD 21/97 - The Assessment of Highway Bridges and Structures. This document details specific guidance for the assessment of masonry arches including load factors, techniques for transverse load distribution and live load impact factors. Further details on design loading and how loading criteria has been merged with the Austroads Bridge Design Code (ABDC) are given in section 2.2.

A live load rating factor based on A160 axle loading at ULS was calculated to be 0.44. This result indicates that at the ultimate limit state full A160 axle loading is over twice the capacity of the bridge.

2.         STANDARDS

2.1    General

The specification and standards for the earlier live load strength assessment and the design of bridge strengthening is based on the technical procedures that have been developed by Gifford and Partners for the special assessment and strengthening of masonry arches in the UK. These procedures have been adapted for Red Bridge and are outlined in Appendix A.

2.2    Design Loading

Live load configurations, nominal axle loads and axle geometry, for assessment and design of strengthening is as far as possible in accordance with the Austroads Bridge Design Code (ABDC) - draft version 5.1. The differences between the loading used for assessment and design as a consequence of merging ABDC with BD 21/97 (ABUK) and the literal ABDC are discussed in detail below.

Tables 2.1, 2.2 and 2.3 show comparisons of axle loads and ultimate limit state (ULS) load factors for A160, S1600 and M1600 loads.

2.2.1    Loaded lanes

Lane widths of 2.5m have been used in place of the ABDC 3.1m. In addition lane factors are different. Loadings calculated according to ABUK criteria, the criteria used for the design, use lane factors of 1.0 whereas loadings to ABDC use lane factors of 1.0 in the critical lane and 0.8 in the adjacent lane. The analysis is based on a 1m strip with the critical transverse position between loaded lanes. Here no transverse load distribution to less severely loaded parts of the bridge such as the footways is possible. However, to allow a comparison to be made between ABUK and ABDC criteria an adjustment in the effective lane width has to be made to allow for the differing ABDC lane factors. The adjustment gives rise to the effective lane width in the tables.

2.2.2    A160 Loading

Table 2.1 shows the load factors associated with single axle A160 loading. It shows that the total ULS load used for the design (ABUK) exceeds the ABDC requirements by almost a factor of two. This difference is due to increased lane factors, increased impact factors and reduced lane width. The generic bridge impact factor in ABDC at 1.3 is the main factor in the difference and is considered to be low. Research in the UK suggests that impact factors for masonry arches should be 1.8 but applied to only one axle at a time. Including the UK impact factor, shown in the table with (), but keeping to ABDC lane loading suggests a reduction in the effective loading of 28% may be warranted. However, if this were to be taken into account it would not alleviate the need for strengthening.

 

Table 2.1 A4160 Loading

 
Description ABUK ABDC ABDC/ABUK
Axle load [kN] 160.0 160.0  
Effective lane width [m] 2.5 3.33  
Critical load width intensity
[kN/m]		 64.0 48.1 0.75
Ultimate load factor 1.9 1.8  
Impact factor 1.8 1.3 (1.8)  
Total factor 3.4 2.34 (3.24) 0.69
Total load width intensity
[kN/m]		 217.6 112.6 (155.8) 0.52 (0.72)

 

2.2.3    S1600 Loading

Table 2.2 shows ABDC S1600 loading criteria which, as Red Bridge is short in length, is never critical. M1600 loading is critical due to the increased axle loads. It is presumed that the increased axle loads are due to vehicle dynamic behaviour.

Table 2.2 S1600 Loading

 
Description

 

 

 ABUK ABDC ABDC/ABUK
Critical
axle 		 Other
axles		 Critical
axle		 Other
axles
Axle load [kN] M1600 always
critical		 80.0 80.0  
Lane width [m] 3.33 3.33  
Critical load width intensity [kN/m] 24.0 24.0 N/A
Ultimate load factor 1.8 1.8  
Impact factor 1 .0 1 .0  
Total factor 1.8 1.8 N/A
Total load width intensity
[kN/m]		 43.2 43.2 N/A
Three axle load total [kN/m] 129.6 N/A

 

2.2.4    M1600 Loading

Table 2.3 includes a comparison of M1600 loading criteria. ABUK uses the S1600 axle loads and a UK impact factor to include all dynamic effects. It is assumed that impact for ABDC is partially included by the axle loads within the definition of M1600 and partially due to the structure related dynamic factor according to clause 2.3.11.2 for buried structures such as culverts. The dynamic structural behaviour of culverts with fill above is assumed to be similar to masonry arches. Dynamic load allowance based on natural frequencies whilst being appropriate for beam type bridge decks is not appropriate for masonry arches. Masonry arches are over damped systems that do not vibrate. Comparison of the total overall axle loads gives a 2% difference between ABUK and ABDC. Hence, the loading criteria used in the design of the strengthening is insignificantly different from that in ABDC.

2.2.5    Accidental Loading

Accidental live loading onto the footways is considered to be an infrequent event and is less likely to cause accumulated damage. For this reason reduced load factors can be used. The following departure from standard has been developed in the UK for this type of loading on masonry arches and has been used for the footways over Red Bridge.

Accidental live loading on the footways will be based on the normal carriageway loading used to assess masonry arches and in accordance with BD 21/97 para. 6.23. However, gfL, will be based on the ultimate limit state including the effects of impact and overload conditions alone and excluding the accumulated damage effects of regularly applying the load. This approach seems reasonable as accidental loading should be a rare event. Referring to BD 21/97 para. H1 gfL for axles including allowance for impact will be 2.52 instead of the usual 3.4. Without impact a value of 1.4 will be used for gfL instead of the usual 1.9. Additionally, unlike the provisions of BD 37/88 accidental live loading will also be considered in conjunction with primary live loading.

Table 2.3 M1600 Loading

 
Description

 

 

 ABUK ABDC ABDC/ABUK
Critical
axle 		 Other
axles		 Critical
axle		 Other
axles
Axle load [kN] 80.0 80.0 120.0 120.0  
Lane width [m] 2.5 2.5 3.33 3.33  
Critical load width intensity [kN/m] 32.0 32.0 36.0 36.0 1.13
Ultimate load factor 1.9 1.9 1.8 1.8  
Impact factor 1.8 1.0 1.21 1.21  
Total factor 3.4 1.9 2.18 21.8 0.91 (mean)
Total load width intensity
[kN/m]		 108.8 60.8 78.5 78.5  
Three axle load total [kN/m] 230.4 235.4 1.02

 

2.2.6    Other Loads

Other live load effects such as centrifugal forces, wind on vehicles, axle lift-off are insignificant for Red Bridge.

In addition loadings such as temperature range, temperature difference, wind, fatigue are known not to be critical for masonry arches and, therefore, have not been considered in the design of the strengthening.

2.3    Strength

As with the strength assessment the ultimate strength of the masonry barrel working compositely with the fill is calculated automatically during the non-linear numerical simulation. Additionally, the strength of the retrofitted Cintec anchors used to provide extra strength is also included in the simulation. Material modelling assumptions and verification processes are described in Appendix A.

Similar to the model developed for existing bridge strength the model that has been developed for the design of strengthening and including anchors is also in two dimensions and uses a strip based calculation. The live load intensity on this strengthened strip is based on the empirical transverse load distribution rule given in BD 21/97. It includes the influence of fill depth, lane widths, kerb lines, footway widths (not loaded), the position of the edge of the barrel and any significant longitudinal cracks that may be present.

 

3.         SOURCES OF INFORMATION

3.1    General

Extracts from the tender documents and the ABDC have been supplied by CLS Cintec Australasia Pty Ltd and used to form the basis of the brief The remaining technical specification of the design of strengthening is defined in Appendix A.

3.2    Computer Software

The finite discrete element computer program ELFEN Explicit (Archtec version - V2.8.0a_MT dated 19/02/99) has been used for the numerical simulation of Red Bridge. The software is written by Rockfield Software Ltd., University of Wales College Swansea and the Archtec modelling system developed by Gifford and Partners. Both organisations are teamed together within the Archtec masonry arch strengthening system joint venture. Cintec anchors are represented using the Rockbolt facilities within this version of ELFEN.

The background and relevant applications for ELFEN and the discrete element technique are described in the earlier report(2).

3.3    Existing Bridge Model

The discrete element model developed for the load assessment of the existing bridge was used in this investigation for the design of strengthening. All material and geometric parameters as well as modelling assumptions are discussed in detail in the first report. However, one minor modification was made to the model. The span geometry was altered slightly to ensure conservatism in the design and to reflect the true shape of the structure as surveyed. Figure 3.1 shows the slightly modified span arrangement.

A geometric survey of Red Bridge was carried out by a local surveyor during January 2000. This has allowed the actual arch geometry to be used in the analysis but most importantly provides accurate surface representation for setting out calculations necessary for the strengthening works.


Figure 3.1 Red Bridge Span Geometry used in Strengthening Design

4.        METHOD OF STRENGTHENING

The Archtec method of strengthening involves accurate placement of retrofitted reinforcement to boost the capacity of the masonry arch barrel. Retrofitting of reinforcement is achieved by using Cintec anchors. These anchors consist of stainless steel reinforcement surrounded by a cement based grout. The grout provides a shear interface between the reinforcement and the masonry whilst the reinforcement carries axial load. The grout is pumped into a sock around the reinforcement which inflates during installation thereby preventing grout leakage and expelling any air and water. The reinforcement is partly mechanically and partly chemically bonded to the masonry once the grout has cured. Anchor parameters such as the diameter of the drilled hole that controls the perimeter area of the grout, reinforcement size and transverse anchor spacing are adjusted to suit the particular bridge. The structural analysis described in section 5 is used to prove the design.

Sufficient extra barrel strength is normally generated by using the anchors to improve the bending resistance of the barrel at approximately the quarter points in circular arches. Modifications to this basic arrangement are used if the barrel has insufficient shear strength or if there is very little fill. Other benefits from Archtec strengthening on the fabric of the bridge for a given load are given below.

  1. The area of masonry in compression in the barrel at the position of potential hinges is increased because of the added bending strength. This reduces the level of peak stress in the masonry.
  2. The horizontal reactions at the springing points of the arch are reduced.

     

    5.        STRUCTURAL ANALYSIS

    A two dimensional plane strain model of the bridge was developed using the discrete element (DE) technique and the computer program ELFEN. The model is shown in Figure 4.1 and is similar to model type S3R3 as defined in Table 5.1 in the strength assessment report(2). The actual geometrical arrangement of the approximately circular and segmental arches were based on the results of the site investigation and

    shown in Figure 3.1. The software was run on a single processor PC type P3 600 under the NT4 windows operating system.

     
    Figure 4.1 Finite Discrete Element Model Developed for Strengthening Design

     

    The DE method is well suited to simulation of non-homogenised continuum and in the assessment of Red Bridge has been used to model the composite behaviour of the arch rings, piers, fill and surfacing. This process is described in detail in the first report. A description of the material models that have been used in the assessment are included in Appendix A.

    The strengthening to be installed into the arch barrels was also included in the model by using line elements to represent the anchors. The modelled anchors incorporate the nonlinear behaviour of the anchors at ULS and allow any failure mode to be predicted. Representation of the strengthening allowed the strengthened bridge to be tested numerically. The design process aimed at optimising the anchor arrangement included several simulations. The results of the simulations corresponding to the final design are included in this report.

    Part of the model is shown in Figure 4.2 and shows the anchor model overlying the DE representation of the masonry barrel. The following properties of the anchors are represented.

  1. The non-linear axial strength and stiffness of the stainless steel is modelled using a von Mises yield criteria.
  2. The non-linear behaviour of the grout to masonry shear interface is modelled including bond stiffness, maximum bond shear stress and maximum bond slip. Once maximum slip is reached that part of the anchor is completely detached from the masonry.
  3. The anchor mesh is independent of the masonry mesh but attached along its length using shear coupling elements to attachment points automatically established within the masonry elements. The shear coupling elements provide the grout to shear properties described in (ii) above. Their position is marked by the nodes along the anchor line elements, see Figure 4.2.
  4. Additional checks were also made on the stainless steel to grout interface which is normally never critical.

     
    Figure 4.2 Modelled Cintec Anchor

     

     6.        RESULTS

    Results from the analysis of the bridge including the strengthening are given in Appendix B. All results are at the ultimate limit state.

    6.1    Masonry

    Typical deflection and stress results are included in Figure B.1 and B.2 in Appendix B respectively. Comprehensive results corresponding to the full set of calculations are not included.

    Figure B.1 shows contoured vertical deflection in the masonry as the three axles of M1600 loading traverse the bridge. Peak vertical deflections under ultimate loads are predicted to be less than 10mm. It is known from full scale tests(3,4) and previous analytical studies that apart from increasing the strength of the bridge the anchors also reduce peak deflections and increase vertical stiffness under similar loads.

    Figure B.2 shows example stress contours for the M1600 loading. Principal compressive stresses are shown suitably scaled for results in the fill. These contour diagrams show the largely hydrostatic stresses at the abutments together with the higher stresses immediately below the vehicle. Zones of white mark thrust in the masonry and clearly show load eccentricity in the piers.

    6.2    Cintec Anchors

    Figures B.3 to B.5 in Appendix B show predicted results in the anchors for the first three rows. Anchor numbering is shown in Figure 6.1 below.

     
    Figure 6.1 Anchor Locations and Numbering

     

    Figure B.3 shows typical axial stress results for the first three anchor rows under M1600 loading. The graphs show the stress histories at five positions along each anchor as the load traverses the bridge. Anchor 1 is first put into tension as the vehicle starts to approach the centre of span 1 with a peak value of approximately 50 N/mm2 before reversing to a value of -30 N/mm2 as the vehicle leaves the span. Similar patterns are predicted for anchors 2 and 3 with an overall peak absolute stress of 70 N/mm2. The graphs also show small residual stresses. The serviceability limit state residual stresses are insignificant.

    Figure B.4 and B.5 show shear coupling stresses and slip displacement between the reinforcement and the masonry. The levels of both coupling stress and slip are well below the maximum values found from full scale test verification. The peak coupling stress is approximately 1.5 N/mm2 which is equivalent to a peak grout perimeter shear stress of 0.65 N/mm2. The slip displacement arises from the stiffness of the grout and even at ULS remains well within elastic limits.

    7.        CONCLUSIONS

    7.1    Final Design

    The final design for strengthening Red Bridge has been developed from the knowledge gained from previous investigations, the material tests and geometric survey reported in the Existing Arch Strength Assessment(2) and data gained from full scale tests. The design has then been tested numerically under the design loading using numerical simulation and the discrete element technique. Drawings have been produced and reduced copies are included in Appendix C. 

    8.        REFERENCES

    1. Department of Infrastructure. Energy and Resources, October 1999, Strengthening of Elizabeth
    River Bridge. Information for Pre-Registration.

    2. Gifford and Partners, February 2000, Red Bridge Strengthening, Existing Arch Strength
    Assessment, Report Number b081I0a007001.

    3. TRL, February 1998, Load Test to Failure on a Ring-Separated Arch Repaired using Cintec Anchor
    System, Project Report PRICE/61/98

    4. Gifford and Partners, February 2000, Baber Bridge Hounslow A315. Strengthening and Load Testing, Report Number b166Oa/0l7/LT.

     

     

     

     

     APPENDIX A Design Specification

    1.0        NAME OF ORGANISATION CARRYING OFF STRENGTHENING

     

    2.0        IDENTIFICATION OF STRUCTURE

     
    2.1     Name and Location: Red Bridge, Campbell Town, Tasmania.
    2.2    Type of Bridge: Multi Span Masonry Arch
    2.3    Obstacle Crossed: Elizabeth River
    2.4    Type of Highway Passing over Bridge: Single two way carriageway, the Midland Highway, approximately 6.7m wide with raised footways of width 1.0m.
    2.5    Permitted Speed of Traffic Carried by Bridge: Unknown

    3.0        DESCRIPTION OF STRUCTURE

     
    3.1    Structure type: Three span masonry arch.
    3.2    Foundation Type: Not known
    3.3    Substructure Type: Substructure to the arch comprises masonry piers and abutments. No strengthening or remedial works are to be undertaken.
    3.4    Superstructure Type: The arch is of brick masonry laid in three rings, each ring built using stretcher courses with squared stopped ends at the barrel edges.
    3.5    Span Arrangements: Masonry arch structure:

    The arch is square with spans of 7.6m. 7.8m, and 7.6m.
    3.6    Articulation Arrangements: None - Masonry arches:

    Masonry build into piers and abutments.
    3.7    Parapet Type: Brick masonry (no strengthening or remedial works to be undertaken).
    3.8    Description of Defects: From the Department of Infrastructure, Energy and Resources (DIER) report(1) and site photographs there appears to be a severe loss of mortar in the inner ring, but otherwise the brick masonry of the barrel appears to be in good condition generally. No major cracking of  the arch barrel is apparent.
    3.9    Proposed Arrangements for Inspection and Maintenance: The Cintec anchors will be embedded in the arch barrel and therefore no arrangement is required for inspection and maintenance.
    3.10    Materials and Finishes: It is proposed to adopt the following characteristic strength: -
      Masonry type weathered brick
      Mortar: 1:2:9 cement/lime/sand
      Characteristic strength: 2 N/mm2
      For Cintec Anchors:-  
      Reinforcement type: stainless steel type 2 ribbed
      Characteristic strength: 460 N/mm2
      Grout/masonry ultimate average shear strength: 0.5 N/mm2

    4.0        ASSESSMENT CRITERIA

    4.1    Live Loading, Headroom, Authorities:

     
    4.1.1    HA Loading In accordance with Austroads Bridge Design Code (ABDC) (A160 and M1600 vehicles) using load factors and transverse distribution from UK Highways Agency BD 21/97.
    4.12    HB Loading None.
    4.1.3   Footway Loading In accordance with Departure from Standard
    4.1.4    Provision for Exceptional
    Abnormal Loads    		 None
    4.1.5    Authorities Consulted and Any Special Conditions Required Department of Infrastructure, Energy and Resources
    4.2    Relevant Standards List of Relevant Documents from the TAS and DMRB - see Appendix A.
    4.3    Proposed Departures from Standards given in 4.2 and 4.2.1. Accidental live loading on footways - see Appendix C.

     

     
    4.4    Proposed Methods for Dealing with Aspects not covered by Standards given in 4.2 and 4.2.1. The assessed strength of the composite arch barrel will be undertaken directly in the non-linear analysis of the arch. The structural performance of the bridge and the ability to predict ultimate strength has been verified against full scale tests(2).
    5.0        STRUCTURAL ANALYSIS  
    5.1    Methods of Analysis proposed for Arch Barrel Strengthening The masonry arch bridge including the multi-ring barrel, masonry piers and abutments, and fill will be analysed using the finite/discrete element numerical method and the Archtec version of the computer program ELFEN Explicit by Rockfield Software Ltd See Appendix B for details.
    5.2    Description and Diagram of Idealised Structure to be used for Analysis A 2D plane strain model will be developed of the bridge based on the geometry under the carriageway. The masonry will be represented non-homogeneously by separately modelling units and mortar. Thefill will be modelled as a non-linear continuum The following material models will be used.
      Masonry units: Non-linear Von-mises in compressive domain
      Masonry mortar: Coulomb friction
      Fill: Non-linear Rankine
      Cintec anchors: Non-linear Von-mises
      Masonry/fill/concrete: Coulomb friction
      The initial and permanent stress state will be calculated as a construction event before the introduction of the live loading. Figure 1 shows the idealised structure. Transverse distribution of live load will be in accordance with BD 21/97.

     


    Figure 1 Finite/Discrete Element Model General Arrangement


     
    5.3    Assumptions intended for Calculation of Structural Element Stiffness Structural element stiffness is calculated directly by the analysis by accurate representation of masonry component parts at a fundamental level This is equivalent to preventing any direct tension across any mortar joint. Evolving cracks associated with different loads will therefore cause structural elements to have automatically calculated and possibly unique stiffnesses.
    5.4    Earth Pressure Coefficients (ka, ko, or kp) to be used in design or earth retaining elements. Mobilisation of active and passive pressure effects will be calculated directly by the analysis. Passive and active pressures develop as the barrel deforms with the fill being able to support carriageway loading and develop thrust lines by biaxial compression.
    6.0        GROUND CONDITIONS  
    6.1 From the report provided the structure(1) has no reported signs of structural distress to the substructures and foundations.
    7.0        CHECKING  
    7.1    Proposed Category of Checking Checked independently of Design Team
    7.2   If Category 11, Name of Proposed Independent Checker Not applicable.
    7.3    Erection Proposals or Temporary Not applicable.
    Works for which the Contractor will be required to arrange an Independent Check listing the parts of the structure affected. Not applicable
    8.0        DRAWINGS AND DOCUMENTS  
    8.1    List of Drawings (including documents) and Documents accompanying the submission: Approval in Principle References:

    1.   Department of Infrastructure. Energy and Resources Strengthening of Elizabeth River Bridge Information for Pre- Registration. October 1999

    2.   TRL. February 1998, Load Test to Failure on a Ring-Separated Arch Repaired using Cintec AnchorSystem. Project Report PR CE/6l/98.

    Drawings included in Appendix C

    Appendices:

    A.    Schedule of design documents relating to highway bridges and structures TAS and DMRB (not included)

    B.    List of computer programs with descriptions (next sheet)

     

    ELFEN Explicit Version - V2.8.0a production onwards

    ARCHTEC Version - V2.8.0a_MT dated 19/02/99

    by Rockfield Software Ltd., University of Wales College Swansea 

    Finite Discrete Element Analysis Solver

    Background

    The origins of the discrete element technique can be traced back to the late 1960s where it was developed to investigate the behaviour of jointed rock. Later improvements included the introduction of deformable behaviour and more recently work has concentrated on improved physical models and better computational efficiency. The computer program ELFEN by Rockfield Software Ltd at The University of Wales, Swansea represents the state of the art in this technology. ELFEN is the only industrial quality  finite discrete element package in the world and in the construction industry is exclusively used by Gifford and Partners.

    Applications

    The finite discrete element method is well suited to simulation of non-homogenised continuum such as masonry, concrete and soil. By representing separate parts that can deform and interact with each other highly dynamic and non-linear systems both in 2D and 3D can be modelled more simply at a fundamental level. Many thousands of parts can be represented each with prescribed friction/contact laws at their boundaries. The capability to evolve further parts by fracturing into separate fragments is also possible by using limiting tension nonlinear material models and advanced mesh adaptivity schemes. Efficient solvers based on explicit dynamic algorithms enable many classes of problem to be solved that would be near impossible by conventional analysis. Typical applications include.

    ·        Numerical simulation of masonry used for buildings and bridges under dynamic and static loads. Considerable experience has been gained in seismic, blast and ultimate static strength applications.

    ·        Numerical modelling of vehicle impact with experience gained in crashing of light passenger vehicles and the simulation of major vessel collision protection systems.

    ·         The prediction of the ultimate strength of complex reinforced concrete assemblies in bridges.  

    APPENDIX B

    Result Extracts for the Strengthened Bridge - Final Design  

     

      Text Box: Figure B.1 Vertical Displacement under ULS M1600 loading (legend in m, positive is up)