update孟加拉O-Cell法桩基静载试验方案提交.doc

GOVERNMENT OF THE PEOPLE’S REPUBLIC OF BANGLADESH
OFFICE OF THE PROJECT DIRECTOR
PAIRA BRIDGE (LEBUKHALI BRIDGE) CONSTRUCTION PROJECT
ROADS AND HIGHWAYS DEPARTMENT
ROAD TRANSPORT AND HIGHWAY DIVISION
MINISTRY OF ROAD TRANSPORT AND BRIDGES

CONSTRUCTION OF 1470 METER LONG PAIRA BRIDGE (LEBUKHALI BRIDGE) OVER THE RIVER PAIRA INCLUDING APPROACH ROAD, BANK PROTECTIVE AND RELATED WORK ATTH KM BARISAL-PATUAKHLI ROAD(N-8)
PAIRA BRIDGE (LEBUKHALI BRIDGE)

Loading Test Project of the Piles
试桩静载试验实施方案

中国·北京建筑大学
北京市城市交通基础设施建设工程技术研究中心
中国·黑龙江路桥一公司
Beijing Urban Transportation Infrastructure
Engineering Technology Research Center
BUCEA, BEIJING CHINA
No. 1st Branch of Heilongjiang Road and Bridge Co., Ltd., Haerbin CHINA

2016-02-21

PAIRA BRIDGE (LEBUKHALI BRIDGE)
CONSTRUCTION PROJECT
-----Loading Test Project of the Piles
试桩静载试验实施方案
目录

1工程概况/Engineering background 3
1.1桥梁概况/Bridge configuration 3
1.2试桩概况/ Outlines of the testing piles 3
2试验依据及要求/Test basis and requirements 6
2.1试验依据/Test basis 6
2.2试验要求/Test requirements 6
3试验原理/ Test principles 7
4实施方案/Test project 11
4.1试桩位置/ The location of testing piles 11
4.2荷载箱的选择/ The choice of loading cells 12
4.3测试仪器安装/ Installation of test instruments 14
4.3.1荷载箱和连接的压力管线/Load box and pressure pipeline to be used in connection its connected pressure pipeline 14
4.3.2振弦式位移传感器/Vibrating displacement sensor 15
4.3.3应变杆/Strain bars 15
4.4.4振弦式应变计/ Vibrating strain extensometer 15
4.3.5塑料管/Plastic pipe 15
4.3.6动力组件/Power components 15
4.3.7安装基准梁及数据采集系统/The iInstallation of reference beam and & data collectionng system 16
4.4试桩进度安排/ Testing SchedulreTest schedules 17
4.5现场测试/Field TestTesting in site 17
4.5.1端部承载力试验（3.5m试桩) /Bearing capacity test at end of pile of pile end (for Φ3.5m test piles) 17
4.5.2总承载力和分层侧壁摩擦力试验（3.5m试桩) /Total bearing capacity test & Test of total bearing capacity and layered sidewall friction for Φ3.5m test piles 19
4.5.3总承载力和分层侧壁摩擦力试验（其它试桩)/Test of total bearing capacity and layered sidewall friction test (for Other test piles) 20
4.6结果分析/Analysis of test results 20
4.7报告内容/Report contents 20
5需要业主和施工方提供的协助/ Needed assistance provided by owners and constructors Help need to be provided by owner and constructor 21
6验证荷载数量及观测耗材预估/Estimation list of proof load and observation materials 23
7附件/Attachments 25
7.1 O-C安装试验过程/ The process of O-Cell installation test Installation test procedure of O-Cell 25
7.2 囊式荷载箱安装试验过程/Installation and test procedure of capsule-type load cell 26
7.3 国产设备及试验性能简介/Introduction to the domestic equipment and its test performance 27
7.4 相关业绩简介/Introduction to our relevant achievements 28

1工程概况/Engineering background
1.1桥梁概况/Bridge configuration
Bridge configurations as based on the Employers requirement have been summarized below. Outline configurations for Main Bridge and Extra-dosed type of super structure maintaining minimum span requirement by the consultants. 需要中文原文？ The height of tower will be within the limit set by the Civil Aviation Authority for the flight path.
1) 桥梁长度/Length of the Paira Bridge
主桥/Main bridge：
630m(115m+2×200m+115m)
引桥(高架桥)/Bridge with viaduct：
840m
主跨/Main span：
200m
2) 桥面布置/Bridge deck
行车道宽/Carriage way width：
2×7.3m
人行道宽(含路缘石)
Width of/Footpath with Kerb：
2×1.10m (Minimum)
防撞墙宽/ The width of bump wall：
0.305m (Minimum)
中间带宽
Width of/Central barrier/ median：
2.96(Minimum)
上部结构类型
/Types of superstructure：
Pre-stressed concrete Extra-dosed Box-Girder
3) 结构类型/Types of structure
上部结构类型
/Types of superstructure：
预应力箱梁、预应力混凝土斜拉桥箱梁
/Pre-stressed Concrete Box-Girder, Pre-stressed concrete Extra-dosed Box-Girder
下部结构类型
/Types of substructure：
钢筋混凝土（桥台)、实体墩、竖井、箱型墩塔
/RCC Abutments, Reinforced Concrete Solid Piers, Shafts, Box-Type Piers /Pylon
4)基础类型/ Types of Foundation
:斜拉桥主墩的基础
/Foundation below of the Main Extra-dosed Span
.5m钢筋混凝土圆形桩
/RCC Solid Circular Pile with 3.5m diameter
引桥的墩台基础为
/ The pier foundation of approach span
2.5m/1.5m钢筋混凝土圆形桩
/RCC Solid Circular Pile for Viaduct Support span with 2.5 m/1.5 m diameter
1.2试桩概况/ Outlines of the testing piles
工程师指定在主桥桥墩P16, P17, P18,P19和P20位置选择工作桩或制作试桩进行奥斯托堡法加载试验。
P16和P20桥墩桩基直径为2.5m，初步设计桩长110m；P17, P18和P19墩塔桩基直径为3.5m，初步设计桩长130m。
初始试验在试桩上进行，试桩验证荷载不超过设计荷载的250%。然后在工作桩上进行加载试验，工作桩验证荷载规范没有规定，但是根据规范中工作桩作为反力桩的要求，应控制桩顶位移不超过0.5mm。
The Osterberg Load Test will be taken at the main bridge drawings P16, P17, P18, P19, and P20, which will be specified by project engineers either through working piles or building test piles. have been carried out at the place where engineers specifies to choose working piles or making test piles in the main bridge from drawings at page 16-20.
The diameter of bridge pile foundation at the pageon P16 and P20 is 2.5m, and its pile length of preliminary designthe preliminary design of its pile length is 110m. The diameter of bridge pile foundation at the page on P18 and P19 is 3.5m, and its pile length of preliminary design the preliminary design of its pile length is 130m.
The initial test will be carried out on test piles, whose verification load should not exceed the design load of 250%250% of the designed load. Then the loading test will be carried out on working piles, whose top displacements should not exceed 0.5mm and whose verification load should not specially be demanded according to the code requirements while a working pile is used as a counterforce one.based on the requirements of working piles as counterforce one in the code requirements, though it is not regulated in the verification load code.

图1-1 主桥立面图 /Fig.1-1 Elevation of the Main Bridge

表1-1 试桩工程数量表/Table 1-1 Quantities of pilot test piles
O-cell tests (Osterberg cells) to be carried out at pile locationP16, P17, P18, P19 and P20 all as directed by the Engineer.
单位/unit
数量/num
For 2.5m dia cast-in-situ RCC piles-Design vertical load 50MN.
--
--
i) Initial pile load test on pilot/non-working pile(including cost of pilot pile). Load test vertical load 125MN.(250%)
Nos.
1
ii) Routine pile load test on working piles. Load test vertical load 75MN.(150%)
Nos.
2
For 3.5m dia cast-in-situ RCC piles-Design vertical load 110MN.
--
--
i) Initial pile load test on pilot/non-working pile ( includingcost of pilot pile). Load test vertical load 275MN.
Nos.
1
ii) Routine pile load test on working piles. Load test vertical load 165MN.(150%)
Nos.
3

2试验依据及要求/Test basis and requirements
2.1试验依据/Test basis
[1] Paira Bridge Construction Project Tender Documents: Technical Specification.
[2] The AASHTO LRFD Bridge Specification (3rdEdition,2004).
[3] The AASHTO Bridge Design Specification (6thEdition,2012).
[4] ASTM D1143-07：Standard test methods for deep foundations under static axial compressive load.
[5] Optimum loading specifications for O-cell bi-directional static load testing.
[6] TheIndustry Standard of the People’s Republic of China: Pile static load test with self-balancing method (JT/T 738-2009).

2.2试验要求/Test requirements
1)试桩制作/The preparation of pilot test pile
测试桩应选择与工作桩相似水文地质环境、采用相同设备和材料进行施工。试桩成孔的尺寸、形状位置必须合乎设计要求，需进行成孔质量检测。
Each pilot test pile shall be constructed in a manner with similar hydrogeological environmentto that to be used for the construction of the working piles, and by the use of similar equipment and materials. The hole size, the pile shape and the position must accord withshall follow the design requirements, and the quality detection of the holes should be required. Any variation shall only be permitted with prior approval.
2)加载设备/ Loading equipments
根据试桩桩径、预估极限承载力大小的具体要求，可选用单个荷载箱，也可以多个并联布置；为了满足特定的要求，荷载箱可以单层布置，也可以多层布置。每个荷载箱在使用前均经过授权计量单位进行压力～荷载的标定。选用的荷载箱直径应小于桩径，荷载箱一般焊接在主筋上。加载设备应控制在1.5倍的工作压力下不破坏。
A single load cell or multiple ones with parallel arrangement can be chosen according to specific requirements of pilot test pile diameter and its estimated ultimate bearing force. In order to meet the specific requirements, the loading cells can be single-layer arrangement and also be multilayer arrangementarranged in single layer or multiple layers. All cCalibrations load and pressure for each load cell beore use must be calibrated by authorized measurement department.The load cell diameter of the load cell should be less than the diameter of the pile, and it is generally soldered to the main steel bar. The loading equipment should be controlled without damage at 1.5 times of the working pressure.It is at 1.5 times the working pressure that the loading equipment should be controlled without damage.
The hydraulic jack, pump, hoses, pipes, couplings and other apparatus to be operated under hydraulic pressure shall be capable of withstanding a test pressure of 1.5 times the maximum working pressure without leaking.缺中文原文
3)注浆/Grouting
工作桩试验完成后，通过预留的注浆管（直径25mm)对试验过程中由荷载箱工作形成的桩身开裂空间进行注浆，以作永久性封闭。
After the work of pile test is finished, the pile cracking space formed by the working of load cell must be grouted through the reserved grouting pipe whose diameter is 25mm so as to keeping permanent closure.

3试验原理/ Test principles
1)奥斯托堡法The Osterberg load test method
Osterberg Cell Load Test（简称为"O-Cell试验" )，是由美国西北大学Prof. Osterberg于1991年创导的一种独特的桩基荷载试验方法，简称奥氏法。其利用桩的自重、桩周土的摩擦力与桩端土阻力作为一对反力的基本原理，借助埋设于桩身（底)的压力盒向上、向下同时施加荷载，以独立地获取桩侧阻力～位移曲线及桩底阻力～位移曲线。
奥氏法的核心设备是称为O-Cell（国内通常称之为"荷载箱"或"压力盒")的大吨位液压千斤顶。试验时通过桩顶液压管路向 O-Cell加载，O-Cell向下的作用力由桩端承载力平衡，向上的作用力由桩身的侧摩擦力平衡。一般将O-Cell放置在桩底的底部，形象地称为桩底加载法。经过二十多年的不断探索改进，现在O-Cell除了放置于桩的底部外，还可以放置在桩身不同中的不同部位，也可以在同一根桩内放置若干的O-Cell。
常规桩顶加载试验的桩顶荷载P等于桩侧摩阻力F和桩端阻力Q之和，即P=F+Q，不计试桩前桩身自重W在桩端的反力。奥氏法试桩时通常采用荷载箱在桩底部产生向上、向下二个方向的荷载P0，向上的荷载P0=W+F，向下的荷载与桩端的桩身自重反力及由加载产生的端部反力增量Q之和平衡，即P0=W+Q，受力机理和桩顶加载相同。于是该二种试桩方法的荷载换算如下：P=F+Q=（P0 -W)+（P0 -W)=2 P0 -2W （其中O-Cell加载量P0 =液压表读数×标定常数)。
Osterberg Cell Load Test, i.e. O-Cell Test, is a unique method of pile load test method created and guided by Prof. J. Osterberg at Northwestern university in 1991. Based on the balance principle of a pair of counter forces between the pile weight and the counter directional forces including soil friction force around pile and resistance force at the bottom end, such curves as between resistance around a pile and displacement, and between resistance at the bottom end and displacement, will be obtained respectively, while the loads are applied from the upward and the downward simultaneously by means of the pressure cells which are located at the middle pile or at the pile bottom.
The O-Cell, aThe key equipment of the O-Cell method, which is commonly referred to as "load cell "or "pressure cell" in China, is a large tonnage hydraulic jacks. When the O-Cell load test pile is carrying out, the load to O-Cell is applied by hydraulic pipeline at the pile top, and here the downward force of O-Cell is balanced by bearing capacity at the end of the pile and the upward force is balanced by the friction force around pile. While the O-Cell is placed at the bottom of the pile, it is generally vividly called loading method of pile bottom. After 20 years of continuous exploration and improvements, the O-Cell can not only be placed at the bottom of the pile, but also be placed at different parts of the pile, especially and many O-Cells can be placed in a pile.
The pile load P of conventional pile load test is equal equals the friction around a pile F and the resistance at the bottom of a pile Q, that is P = F + Q, without including the reaction produced by the self weight W of a pile at the end before testing. When O-Cell's method is used in working pile, usually use load cell to produce load P0 is produced by load cells in two directions (upward and downward) at the bottom of the tank. The upward load P0=W+F and the downward load is balanced by the weight of the pile and the reaction force increment at end of a pile Q due to being generated by loading, that is P0 =W+Q. The mechanism is same to loading at the top of a pile. So the load conversion of these two test methods is as follows:
P=F+Q = (P0-W)+(P0 -W)=2P0-2W (1)
where O-Cell loading =manometer readings ×calibration constant.

图3-1 奥氏测桩法与传统静载方法原理对比
Fig.3-1 O-Cell pile test method and the traditional principle of comparative static load

图3-2 奥氏测桩法
Fig.3-2 The Osterberg load test method

图3-3 奥氏测桩法实测荷载位移曲线示例
Fig.3-3 The curve sample of the O-cell test pile method measured load displacement

图3-4 奥氏测桩法等效桩顶加载法荷载沉降曲线示例
Fig.3-4 The curve sample of o-cell test pile method of equivalent pile
load-settlement top loading method

2)自平衡法/self-balanced method
奥氏法在国内被业界称为自平衡法，自九十年代后期由美国引入中国，先后有一些国内工程采用自制的O-Cell进行试桩。自平衡法即利用上段桩侧阻力和下段桩侧阻力与端阻的自相平衡的一种测桩法。桩身某一位置，其上段桩身自重及桩侧极限摩阻力之和与下段桩桩侧极限摩阻力及极限桩端阻力之和基本相等，即为平衡点。
近几年来，国内研制成功和迅速推广普及的专业荷载箱（如腔式荷载箱、囊式荷载箱)，在提高桩基安全性、试验成功率、试验安全性、试验准确性的同时，降低了检测项目成本，对自平衡测桩法的发展和完善提供了强有力的支持。
The o-cell was called self-balanced method in the Chinese domestic industry, introduced fromby the United States since 1990s, China has some of the domestic engineering project in China have used using homemade O-Cell to test pile. Self- balanceding method which is to use resistance fromof the top period of the pile and the resistance fromof the descend period of the pile and the end resistance of the phase equilibrium to reach equilibrium. The balance point is a particular location of pile, its weight of top pile and the sum of its frictional resistance of pile side in the upper limit was equal to the sum of the descend period of pile side friction and the pile tip resistance limit.
In recent years, with the successful development and rapid popularization of domestic professional load cases (such as cavity load cases, bladder type load box), the safety of the pile foundation, test success rate, test security, and test accuracy is increasing at the same time, the detection of the project cost is reducing, which provided a strong support for the development and perfection of the self self-balanceding test method.

图3-5 自平衡法测桩原理
Fig.3-5 A sketch of the self-balance pile test

4实施方案/Test project
4.1试桩位置/ The location of testing piles
工程师指定在主桥桥墩P16, P17, P18,P19和P20位置选择工作桩或制作试桩进行奥斯托堡法加载试验。
The Osterberg Load Test will have been carried out at the place where engineers specifies to choose working piles or making test piles in the main bridge from drawings at page 16-20.
Specific locations will be chosen at Main Bridge pier P16, P17, P18, P19, and P20 by project engineers, where Osterberg load test will be taken through working piles or making test piles.
4.2荷载箱的选择/ The choice of loading cells
合格的荷载箱，是测桩成功的必要条件，但绝不是充分条件。 低品质的荷载箱产品，主要表现在加载失败率较高或者加载（线性)性能超差，这将直接影响桩基加载试验的成功率，以及试验数据的真实性和准确性。 
Qualified load cell is a necessary condition of successful, but is not a sufficient condition. Load case of low quality products, mainly displays its failure rate in the loading is higher or load (linear) performance is poor, which will directly affect the success rate of pile load test, and the authenticity