下沙大桥也称为杭州钱塘江六桥钢围堰设计.rar

涌潮河段钢围堰设计

摘要：下沙大桥也称为杭州钱塘江六桥。在该桥位地处钱塘江强涌潮河段，涌潮压力比较大，一般都在56～79Kpa之间。水下基础施工是该桥的关键。
关键词：下沙大桥    钢围堰     涌潮

一、工程概况
1、工程简介
下沙大桥工程项目为杭州市绕城公路东段的主要控制工程，本合同段起点里程桩号为K21+559.25K23+437.538，全长1878.288米，桥跨布置为20×25m+13×50m+（127+3×232+127）/2 米。主桥上部结构为预应力混凝土刚构连续梁组合体系。主引桥、引桥分别为50、25米预应力混凝土先简支后连续的T梁。下部结构主桥为双薄壁墩身，主引桥为墙式墩，引桥为柱式墩身。
下沙大桥主桥单线承台的截面尺寸为25.60×13.40×5.50米，主墩承台设计的封底厚度为4.50米。主墩承台顶面标高为-4.0米，底面标高为-9.50米。设计封底混凝土底面标高为-14.0米。
下沙大桥主墩承台的基桩呈梅花型布置，单线有13根基桩，其中一根为备用桩。在19号主墩基桩的直径为2.0米，其桩顶标高为-9.50米，原设计桩底标高为-88.0米。20号主墩基桩采用变截面的形式，在标高-9.50~-42.0的范围内，桩径为2.30米；在标高-42.0~-96.0米的范围内，桩径为2.0米。
2、气象情况
桥位地区属亚热带气候区，温暖湿润，四季分明，秋旱少雨。多年平均温度16.4℃。极端最低气温-9.6℃，极端最高气温39.9℃。本区域全年主导风以东风为主，北、西风次之，历年最大风速20m/s，平均风速为1.9m/s。桥址位于东南沿海边，易受台风及热带风暴的影响。
3、水文
桥址水域，汛期受洪水控制，非汛期受潮汐控制，由于钱塘江在桥位上游大幅度的收缩，以致潮能集中，潮位增高，潮流动力极强，从而形成了世界闻名的涌潮，本桥位于强潮河段，又处于河湾顶面，水文条件复杂。桥位所
Bore Section steel cofferdam design

Abstract: Xiasha Hangzhou Qiantang River Bridge, also known as the six bridges. In the bridge position is located in the strong tidal bore of Qiantang River, relatively large bore pressure, generally between the 56 ~ 79Kpa. Underwater foundation construction is the key to the bridge.
Keywords: tidal bore steel cofferdam Xiasha Bridge

First, project survey
1, Project Description
Xiasha Bridge Project for the Eastern Ring Road, Hangzhou, the main control engineering, the starting point of this paragraph mileage contract Stake for the K21 +559.25  K23 +437.538, full 1878.288 m, bridge span arrangement for the 20 × 25m +13 × 50m + (127 +3 × 232 +127) / 2 米. Main Bridge is a prestressed concrete rigid-beam combination system. The main bridge, approach bridge, respectively 50,25 m simply supported prestressed concrete continuous T-beam. The main bridge substructure Double Thin pier, the main approach spans for the wall piers, approach bridge pier for the column.
Xiasha Bridge cross-section single cap size 25.60 × 13.40 × 5.50 m, the main pier pile cap design on the back cover thickness of 4.50 meters. Main Pier top elevation of -4.0 m, bottom elevation of -9.50 m. Design of sealing concrete bottom elevation -14.0 m.
Xiasha Bridge pier pile caps were plum-type layout, in-line, 13 foundation piles, which one for the back-post. In the main pier piles 19, the diameter of 2.0 meters, the pile top elevation of -9.50 m, the original design elevation of -88.0 m pile. Main pier piles 20 with variable cross-section of the form, in the elevation range of -9.50 ~ -42.0, the pile diameter is 2.30 m; -42.0 ~ -96.0 m in elevation within the pile diameter is 2.0 meters.
2, meteorological conditions
Bridge location area has a subtropical climate zone, warm and humid with four distinct seasons, dry autumn drought. Annual average temperature is 16.4 ℃. Extreme minimum temperature of -9.6 ℃, extreme maximum temperature of 39.9 ℃. Wind in the region throughout the year leading to the main east, north, west wind the second, the calendar year maximum wind speed 20m / s, average wind speed is 1.9m / s. Side of the bridge is located at the southeast coast, vulnerable to typhoons and tropical storms.
3, hydrological
Bridge site waters, flood by flood control, non-tidal flood control, due to the upstream of Qiantang River in the bridge a significant contraction, resulting in tidal concentration, tide increased, the trend strong momentum to form a world-famous tidal bore, this Bridge is located in tidal rivers, which are on the top bend, hydrological conditions are complicated. The bridge location