大跨度预应力混凝土空心面板服役性态安全评价

Safety evaluation on service behavior of large-span pre-stressed concrete hollow-core slab

宁波某泊位码头结构服役多年,受到海洋大气环境侵蚀、涨落潮等影响,加上现有设计标准有所提高,亟需对该码头涉及到的预应力混凝土空心面板进行安全评价。然而,目前对使用中的预应力结构缺乏相应检测技术规程,不能进行有效评价。为此,根据该码头现场实际情况,采取原位静载试验与数值仿真分析相结合的手段,择优选取单跨跨中截面竖向位移和承载能力为主要评价指标,以雷达深度为检测指标,对其面板进行服役性态安全评价。结果表明,目前面板无外观质量缺陷,整体平整度高,其承载能力、结构变形均在安全指标范围内,码头仍可正常运行。本文提出的评估方法为码头预应力结构寿命周期内结构安全评估和后期加固提供了有力的参考依据。

Under the impacts of the erosion from marine-atmosphere environment and the tidal fluctuations for many years together with the enhancement of the current design standard to some extent during the service of the structure of a berth wharf in Ningbo,it is urgently to make a safety evaluation on the pre-stressed concrete hollow-core slabs related to the wharf. However,there is a lack of the relevant technical code for detecting the pre-stressed structure under service at present,thus effective evaluation cannot be carried out. Therefore,in accordance with the in-situ status of the wharf,a safety evaluation of the service behavior of its facing slab is made by optimally selecting the vertical displacement and the bearing capacity of the mid-span section of single span as the main evaluating index and taking the penetrating depth of radar as the detecting index by means of combining in-situ static loading test with numerical simulation analysis. The result shows that no any appearance quality defects are there on the facing slab at present,of which the integral evenness is high,while both the bearing capacity and structural deformation are within the range of safety index,thus the wharf can still normally operates. The evaluation method proposed herein provides a powerful referential basis for the structural safety evaluation made in the working life period of the pre-stressed structure of wharf and the strengthening in its later period.