预应力混凝土空心板梁火灾损伤特性研究

为探究火灾对预应力混凝土空心板梁受力性能的影响机理,制作10片跨径13 m的预应力混凝土空心板梁进行火灾模拟试验和火灾后的静力加载试验,分析火灾过程中及火灾后的试件状态、梁体内部温度及火灾后的剩余承载能力.结果表明:火灾初期梁体受火面混凝土会随机性爆裂,爆裂削减了钢绞线的混凝土保护层厚度,导致钢绞线火灾中温度显著升高;...

Study of Fire Damage Charateristics of Prestressed Concrete Hollow Slab Beam

To investigate the influence mechanism of fire disasters on the load bearing behavior of prestressed concrete hollow slab beams,ten 13 m-long prestressed concrete hollow slab beams were prepared for the fire simulation tests and the static loading test after fire events.The condition and temperature inside the beams during and after fire events as well as the residual load bearing capacity of the beams after the fire events were analyzed.The tests show that the surface of the concrete beams exposed to fire can burst sporadically,which undermines the thickness of the concrete cover of steel strands,consequently the temperature of steel strands dramatically rose up in fire.As the duration of the fire event extends,vertical cracks begin to occur in the middle of the webs,the beams gradually bend,the temperature inside the beams keep climing up,but the high temperature influence zone mainly appear within the region distancing 10 cm from the surface exposed to fire.The residual load bearing capacity of the beams is related to the duration of a fire event,but the maximum temperature of steel strands in the fire is a key factor.Serious burst and/or loss of concrete cover makes the steel strands experience excessive heat,resulting in severe loss of load bearing capacity of beams after a fire event.