预应力混凝土桩锤击时纵向开裂问题探讨

Investigation of Longitudinal Cracking of Prestressed Reinforced Concrete Piles under Hammer Blow

本文根据预应力钢筋混凝土4组共16根(200cm×25cm×25cm)试验桩受锤击时纵向开裂试验结果,提出了桩受锤击时"横向箍筋约束效应"的计算模式.运用了弹性力学和材料力学的计算方法,对预应力桩进行了冲击计算,导出了预应力桩受纵向冲击时,纵向开裂发生前至发生时的桩内横向拉应力计算公式.据此,探讨了预应力钢筋混凝土桩锤击时纵向开裂的机理,并验算了试验桩的开裂结果.

On the basis of the longitudinal cracking test results of the 4 sets of 16 prestressed reinforced concrete piles (200cm × 25cm × 25cm) under hammer blow , this paper presents a computational model for the transverse-stirrup confining effect on the pile under hammer blow , develops the impact computations for prestressed piles by use of methods in plane elasticity and material mechanics , and derives the formulas for the calculation of the transverse tensile stress of the prestressed pile under the longitudinal impact . These formulas can be used before longitudinal cracking occurs . On these grounds , the mechanism of the longitudinal cracking of the prestressed reinforced concrete pile under hammer blow is investigated and the cracking results of the experimental piles are verified .