预应力CFRP筋混凝土梁受剪性能试验研究

Experimental studies on shear behavior of concrete beams prestressed with CFRP tendons

FRP筋是一种新型预应力筋材,具有轻质、高强、耐腐蚀、抗疲劳等优点,但是其横向剪切强度相对较低,这会影响预应力FRP筋混凝土梁的受剪承载力。通过27根混凝土梁的受剪试验,研究了预应力CFRP筋混凝土梁的剪切破坏形态,以及各种参数对其受剪承载力的影响,并与钢绞线预应力混凝土梁的受剪试验结果进行了比较。研究结果表明:预应力CFRP筋混凝土梁的剪切破坏形态有两种:斜压破坏和剪压破坏;剪跨比和配箍率是影响预应力CFRP筋混凝土梁受剪承载力的主要因素;有粘结预应力CFRP筋混凝土梁的受剪承载力比无粘结预应力CFRP筋混凝土梁要大15%左右;通过引入反映预应力筋种类和粘结条件的2个参数,提出了预应力FRP筋混凝土梁的简化受剪承载力计算式,计算结果与试验数据吻合较好。

As a new structural material,FRP（fiber reinforced plastics） features light weight,high strength,corrosion resistance,anti-fatigue,etc.,and have a bright future when used as a new type of prestressing tendon in engineering structures.The horizontal shear strength of FRP tendon is low,which will affect the shear strength of concrete beams prestressed with FRP tendons.Based on experimental studies on 27 concrete beams prestressed with CFRP tendons,this paper studied the shear failure modes and a variety of parameters on shear strength,and compared the shear performance with concrete beams prestressed with steel strands.Studies show that there are two shear failure modes for concrete beams prestressed with FRP tendons,i.e.diagonal compression and shear-compression.Shear span ratio and stirrup rate are main factors influencing the shear behavior of concrete beams prestressed with CFRP tendons.The shear strength of concrete beams prestressed with bonded CFRP tendons is about 15% larger than that of concrete beams prestressed with unbonded CFRP tendons.A simple formula for computing the shear capacity of concrete beams prestressed with FRP tendons was presented by introducing two parameters,which reflected the type and bonding condition of prestressing tendons respectively.The computed shear capacities of concrete beams by presented formula agree well with the experimental data.