裸梁静载试验加载控制弯矩确定方法

现有方法将加载控制弯矩简单视为未施工前作用裸梁上的恒载(主要为桥面铺装)和设计车辆荷载之和,未考虑桥面铺装的承载能力,致使试验结果不准确。提出了一种基于应变确定裸梁静载试验加载控制弯矩的新方法。基于成桥状态下设计车辆荷载及桥面铺装联合作用下的最大应变,根据其最大应变值通过裸梁截面惯性矩反向计算确定控制弯矩。该方法充分考虑了裸梁至成桥施工及受力过程,在桥梁施工过程中桥面铺装的恒载完全由裸梁承担,成桥后营运过程中部分桥面铺装与梁体协调工作、形成受力整体,共同承担设计车辆荷载。通过工程实例验证,本方法可实现裸梁静载试验控制弯矩的精准化、试验控制的精细化。

Determining the control bending moment of the bare beam in static load test

Because the existing method considers the loading control moment as a sum of the dead load on the bare beam before construction (mainly for bridge deck pavement) and the design vehicle load, the bearing capacity of the deck pavement is not considered, so the test result is not accurate.In this paper, a new method is proposed to determine the loading dominate moment of the bare beam static test.This method is based on the maximum strain with the combined effect of design vehicle loads and bridge deck pavement in the finished bridge state and the dominate moment is calculated reversely by the maximum strain through the second moment of area.This new approach has fully considered the construction and the process from the bare beam to the finished bridge state.The dead load of bridge deck pavement is borne entirely by the bare beam in the process of bridge construction, and a part of bridge deck pavement work with beam to form a stress whole to bear the design vehicle loads.The test results prove that the new method can achieve the precision of dominate moment and the refinement of test control in the bare beam static test.