Method statement for construction of temporary bridge (Thuyết minh biện pháp thi công Cầu tạm)

Biện pháp mô tả chi tiết quy trình thi công Cầu tạm phục vụ thi công hạng mục Cầu chính. Biện pháp được biên soạn dựa trên chỉ dẫn kỹ thuật dự án, tiêu chuẩn AASHTO, TCVN

5.GATHERING MATERIAL, EQUIPMENT, ARRANGEMENT OF SITE 7

5.1Gathering material, equipment 7

5.2Site Arrangement 8

6.TEMPORARY BRIDGE CONSTRUCTION 9

6.1Design Solutions - Construction Technical 9

6.2Temporary Bridge structures 11

6.3Construction process for Temporary Bridge 13

6.4Observe and maintenance process of steel temporary bridges 16

6.5Demolition of temporary steel bridge 18

7.TRAFFIC SAFETY CONTROL 19

8.ENVIROMENT AND SAFETY CONTROL 20

8.1Safety Control 20

8.2Environmental Control 21

9.APPENDIX 23

1.GENERAL DESCRIPTION

1.1Introduction

This method statement provides the details of the procedure, the manpower, the equipment, thematerials and relevant documents related to construction of temporary bridge including the qualitycontrol verifications, the measurement verifications, and also the safety precautions andenvironment protection to be implemented for this work.

1.2Project Information

The project road connects Tbong Khmum district to Kratie province of the Cambodia, stretchingalong the northern, to Kratie province The road passes on a comfortable alignment throughflat/wavy terrain along the toe of hilly land Four (4) rather sharp curves along the road areconsidered non-critical due to adequate super-elevation of the road way and appropriate signage.The traffic on the road is a medium mix of private cars and quite heavy trucks that contributemainly to the road wear The PR.377 and PR377A of RCIP are located in Kratie province Thelength of the PR377 is 35.00 km and the PR377A is 13.593km The location of the packages isshown in Figure-1

Figure 1.2 Location of Contract Package on CW-3(PR377 & PR377A)

1.3Project Objective

The objective of the project is to ensure continued effective use of the rehabilitated national andprovincial road network in support of the economic development in Cambodia It will do so byimproving the institutional and technical capacity of the Ministry of Public Works and Transportfor road maintenance planning, budgeting and operations as well as by expanding of strengtheningmaintenance activities.

The project seeks to contribute to cultivating a road asset management culture within the sectorby: (i) expanding maintenance of the national road infrastructure nationwide and facilitatinginterventions in priority areas, (ii) allocating adequate maintenance funding during the budgetingprocess; (iii) knowledge building in MPWT on road network management, maintenancetechnology and contract management; and (iv) private sector involvement in competitive biddingand performance quality.

Project is expected to bring significant benefits to local residents in six Cambodian provinces,Kampong chham, Tbong Phmum, Kratie, Mondulkiri, Ratanakiri and Stung treng province; byreduced travel times and cost, less arduous journeys and better connectivity along the nationalroad network It is intended that the benefits to local populations are maximized, and to ensure thatthe benefits are shared by local communities.

1.4Topography and Climate

The topography in the project area is mainly flat with some hilly sections and the road elevationvaries from minimum 23.52m to maximum 50.95meter The maximum temperature is around40°C, the annual temperature fluctuates more than 10°C and from 6 – 7°C in a day In hot weatherthe absolute high temperature may be up to 39°C (in April) By contrast, in January the absolutelow temperature may descend to 16°C

1.5Rainfall Records

The available hydrometeorological data such as rainfall are obtained from the Kratie ProvincialDepartment of Water Resources and Meteorology (PDoWRAM) The rainfall station is located at(X=610976, Y=1379728) The data ranged from 1980 to 2019 is considered to conduct frequencyanalysis for hydrologic modeling The 24hr maximum annual rainfall over 3 decades wereextracted for the analysis as shown in Figure 4.1 and 4.2 below From the figure below, it’s clearlyobserved that the highest rainfall over the period was in the year of 1988 with a value above250mm, followed by the year of 1982 as the second highest with the precipitation of above270mm The year 2009 is observed to have above 150mm which was the highest rate over the 10year after 1992 and it was revealed during the Ketsana storm In 2001 was noted as lowest rainfall,it’s reflected to the Drought period.

Figure 1.5.1 Daily Rainfall Ditribution in Kratie 1980-2019

Figure 1.5.2 Rainfall Distribution over 1980-2019

2.1Scope of Works

This is method statement for constructing temporary bridge, serving traffic flow as well assupporting during the construction of the bridge on main road.

Summary table of Temporary Bridge :

Width (m)(Proposed)

b) Technical specification

+ Section 5.1: Concrete of Specifications+ Section 5.2: Reinforcement of Specifications + Section 5.5: Steel Structures

2.3Construction Schedule

Construction Schedule shall be referred to latest approved Schedule.

Organization Chart is as follow:

POLY CHANDA ENGINEERING CO., LTD

PROJECT MANAGER

Mr.WEI JAING

Material Engineer

Mr LAI DE SEN

AMP Manager

Mr.LIN ZHI HUI

Design Engineer

Mr LAI DUY TRUNG

QA/QCManager

construction

5.GATHERING MATERIAL, EQUIPMENT, ARRANGEMENT OF SITE

5.1Gathering material, equipment

All material, equipments are gathered rightly in the site by the roadway.As for the construction equipment for this work, the clarification is as follows:

Steel and other loose construction materials used to construct steel temporary bridges are allpurchased from China.

Steel purchased domestically is transported to Sihanoukville port by sea way, then transported tothe processing place After technical processing is completed, it is transported to the constructionsite and put into production The quantity of each structural material is as follows

As for the construction materials for this work, the clarification is as follows:

Quantities detailwill be shown on

Working Drawing

3

t

7 U-shaped fixture Each

Quantities detailwill be shown on

Working Drawing

5.2Site Arrangementa) Site Preration

During the construction of the temporary bridge, traffic will still be maintained on the mainbridge The contractor will install protective fences, sign systems, night lights and workers toguide traffic on both sides of the bridge

b) Temporary Facility layout

On-site temporary facilities

c) Plan for supply of power, Water, And Ful, Etc.

 Temporary Water Use

The contractor will register to use the local water source for production.Where it is not available, using water shall be transported to the site.

 Electricity Supply

Local electric network will be connected in the power-available place and consideringthe sustainability of construction, the generating set shall be prepared as a standby source of

power in case of power failure Where it fails to connect with local electric network, thegenerating set shall be used.

 Temporary Communication

The fixed telephones and Internet shall be installed in Project Management Office; Keypersonnel shall be supplied with cell phones to facilitate the internal and externalcommunication.

 Supply Sources of Major Materials

Given the quality of material is ensured and adhere to the principle of best use of localmaterials, to make an extensive investigation on material sources, prices, traffic conditions,means and costs for a good economic and technical comparison Choose the best material anddeliver them according to plans In addition to the materials which are supplied by the Employer,asphalt, high strength steel bars, pre-stress wire, bridge bearings will be met by purchasing themin China Most of fuel and oil will be purchased locally, the rest will be purchased from China.

 Supply of Major Workers

We have rich labor and technician reserves which can be delivered to the site as plan,and we can also recruit some labors locally.

6.1Design Solutions - Construction Technical

- The proposed temporary bridge structure is a steel truss bridge with girder using Baileystructure.

- Bridge position, number of spans and bridge length will depend on the main bridge forarrangement as clearly indicated in Section 2.1 of this method.

- Bridge Design Standards AASHTO – LRFD 02 - The Design Load 40 Ton For The Traffic Load Passing On The Temporary Bridge.- The Design Load 75 Ton For construction equipments On The Temporary Bridge

1Summary of Design Solutions

 Input data:

-Calculated span length: Ltt = 9.0 m.-The calculated bridge with 1 lane is designed to be 5.0m wide.-Bridge construction elevation: Bailey steel truss temporary bridge is designed parallel to the

main bridge and during use will have a certain allowable deflection, so to meet the needs ofexploitation, it is recommended to choose the construction elevation bridge is equal to theheight of the main bridge.

98Kn/m2

Vibrating hammerCrane

Design tasks:

-Design the bridge deck girder system: longitudinal girder, horizontal beam, connecting thelongitudinal beam to the horizontal beam and connecting the horizontal beam to the main truss. Design standards:

-Designed according to the process (AASHTO, 2002). Design of load combinations:

-Temporary bridges are designed according to load and resistance factor design (LRFD)

 Materials used for structure:

-Structural steel has :+ Yield strength Fy = 345 Mpa+ Minimum Strength Fu = 450 Mpa+ Elastic modulus Es= 200000 Mpa+ Nominal mass gs= 7850 kg/m3 = 77.09 kN/m3

-Links using high strength bolts.

6.2Temporary Bridge structures

-Based on the traffic volume expected to be equal to the permanent construction, the contractorproposes the temporary bridge structure as follows and conducts structural testing according to thelimit states.

-The steel bridge selected for calculation is a simple span bridge and a continuous span bridgeon fixed elastic bearings.

-The temporary bridges under package CW3-PR377 selected for calculation are simple span andcontinuous span steel structure bridges on fixed elastic bearings.

-The contractor proposes to choose a steel structure with three spans for typical calculations andapplies to all other temporary bridges in the package.

1Structure of Piers and Abutments

- The Pier and abutment structure consists of 2 D800 steel pipes that are driven into the hard soilgeological layer and linked together by 2I32a horizontal beams and diagonal braces.

- The distance between 2 D800 steel pipes is 3.60m.- The length of cross beam 2-I32a is 6.0m

 Determination of steel pile length

- Length of steel pile will be selected and calculated according to AASHTO LRFD 2007 –Bridge Design Specification.

-The pile length is selected to ensure that the pile's bearing capacity by Soil is greater than theAxial force max acting on the pile head.

Qr > Pmax

In which:

+ Qr : Bearing capacity by soil (KN)+ Pmax: Axial force max (KN)- Geological condition and hydraulic condition According to supplementary information finalengineering design report.

- The steel pile length spreadsheet will be prepared by the contractor together with theconstruction drawings and will be submitted to the engineer for inspection and approval separatelyfor each bridge.

Typical of the spreadsheet shown in the attached appendix2Structure of girder

- The bridge girders are used with bailey structure type 2/1 Six Bailey girders are arrangedhorizontally:

Bailey truss structure consists of the following types of materials:

- Profiled steel has the following requirements:

+ Requirement of tensile and bending steel strength Ru > 400 Mpa- Shaped Bailey Panel frame;

- Panel latch;- Horizontal beams - Locking cross beams;- Struts;

- Bracing bar;- Vertical brace;- Boulon links increase hard.

3Structure of Bridge Deck System

- The bridge deck system includes horizontal beams I25b and longitudinal steel C25b.- I25b horizontal girder with length of 6.0m installed on bailey beam system along the

bridge with spans of 750cm.- Bridge railing system installed always on both side of bridge.

6.3Construction process for Temporary Bridge

BAILEY BEAM INSTALLATION

DISTRIBUTION BEAM INSTALLATION

BRIDGE DECK INSTALLATION CONSTRUCTION PREPARATION

TRANSPORTATION AND LIFTINGOF STEEL PIPES

STEEL PIPES DRIVING

PIERS BEARING INSTALLATION

INSTALLATION OF RAILINGS AND WARNING SIGNSSTEEL PIPES PROCESSING

BAILEY TRUSS ASSEMBLY

1 Construction preparation

 Processing and transporting steel pipes.

-Steel pipes are processed by professional manufacturers, when put on site Steel pipes are testedand accepted, the quality meets design requirements, and the specification requirements, thesurface should be free from cracks, air bubbles, scale, interlayer, and other defects.

-Steel pipes are transported to the construction site by flatbed trucks, and the followingreinforcement measures are taken during transportation:

+ Steel pipes are placed horizontally, then steel pipes and column bodies are firmly tied with steelwire and chain hoist.

+ Construction Steel Pies at Abutments, Piers+ The gaps should be filled with wooden squares to prevent the steel pipes from loosening and

causing large vibrations during transportation.-Steel pipes will be calculated and cut - connected by welding connection at the main

reinforcement processing area of the contractor However, with piles with a length greater than12m, the segments will be linked together at the reinforcement processing area arranged at theconstruction site.

-The welding joints must be qualified according to the AWS D1.1 - 183 - E70XX SERIESspecifications, and be tested and approved by the engineer before being put into installation.-Quality of welds: Good welds must ensure that there is no cracking, water leakage or

deformation to a large extent.-Shape of weld: The weld after finishing ensures no cracks The size of the weld is the same, not

too big, not too small, or if there is no broken corner, it will be a beautiful weld.Bailey truss assembly.

-The main girder system of the bridge is composed of panel frames into Bellay type type 2-1.-The truss is installed at the construction site according to the 2-1 truss system with latches.

When installing the truss, some horizontal beams, tie bars, cross beam locks will becombined to reinforce the truss.

-The connections must be carefully checked and accepted by the engineer before installing thebeams.

2 Construction Steel Pies at Abutments, Piers

Preparation of materials, machine, and construction siteDetermine the location of the abutments, Piers.

Determine the location of steel pipes.+ The hole span of the temporary steel bridge is arranged to be a span of 9m.+ Vertical control of steel pipe by total station, and the deviation of the center of the pile does

not exceed 5 cm. Installation of steel pipes at abutments, Piers.

+ The steel pipes of the truss bridge are brought in and closed by a 75-ton crawler cranecombined with a vibrating hammer to vibrate.

+ After the cantilever guide frame is correctly positioned, let the steel pipe pile sink into theground under its own weight.

+ Lift the vibrating hammer and hydraulic clamp on the steel pipe pile head, clamp the steel pipepile head with the hydraulic clamp and check.

+ After the verticality of the pile is satisfactory, start to vibrate the hammer, first move it little bylittle, then connect so that the steel pipe pile does not fall.

+ Time for each vibration is no more than 10-15 minutes.