3受压构件解析

,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,砌体构造,西南科技大学土木工程与建筑学院,3,无筋砌体构件的设计计算,3.1,无筋砌体构件的设计计算,受压构件,受拉构件,受弯构件,受剪构件,内容提要,砌体,构件,砌体,构件,无筋砌,体构件,有筋砌,体构件,受力情形,有无配筋,受压,构件,轴心受压,偏心受压,局部受压,3.1,受压构件的承载力计算,3.1.1 概述,1.砌体构造受压构件,1工程中实际构件：墙、柱等。,2按轴向力合力的作用位置，分：轴心受压和偏心受压。,3按墙柱高厚比的不同，分为受压短柱、受压长柱。,3.1,受压构件的承载力计算,2.偏心距,一般状况下，把计算时e=0的状况归结为轴心受压。偏心受压时的偏心矩表示为：,-,轴心压力设计值。,-,弯矩设计值。,3.1,受压构件的承载力计算,3.高厚比,砌体受压构件也分为短柱3和长柱。以高厚比大小 的大小来判定。,对矩形截面,对T形截面,:不同砌体材料的高厚比修正系数。对烧结一般砖、烧结多孔砖取1.0；对砌块取1.1；蒸压灰砂砖、粉煤灰砖、细料石、半细料石取1.2；对粗料石和毛石取1.5。,H,0,:,受压构件的计算高度；,h,:,矩形截面轴向力偏心方向,的边长，轴心受压时，,h,为截,面较小边长。,h,T,:T,形截面的折算厚度，取,h,T,=,3.5i,，,i,为截面回转半径。,3.1,受压构件的承载力计算,4.,砌体受压承载力计算的目的：,计算在轴向压力作用下的构件截面最大压应力不超过砌体抗压强度设计值。,3.1.2,轴心受压构件,1.,轴心受压短柱：,轴心受压短柱是指,e=0,且,3,的受压构件。,承载力计算公式：,A,：构件截面面积,3.1,受压构件的承载力计算,2.轴心受压长柱：,当高厚比 3长柱时，由于偶然偏心使构件产生附加弯曲应力。因而在一样荷载状况下，长柱截面边缘最大压应力将大于其他条件一样的短柱截面压应力，即长柱受压承载力小于短柱受压承载力。取 为轴心受压稳定系数。,则,轴心受压长柱承载力表达式,为,3.1,受压构件的承载力计算,3.1.3 偏心受压构件,1.偏心受压短柱,当高厚比 3短柱时，偏心受压短柱界面应力分别随偏心距变化而变化，最大截面应力可以按材料力学方法和考虑砌体弹塑性性能方法。,3.1,受压构件的承载力计算,1按材料力学方法,马上砌体视为匀质弹性体，矩形截面边缘压应力：,2考虑砌体弹塑性能,二是考虑砌体弹塑性性能。截面应力分布为曲线分布.通过试验分析,可得矩形截面砌体的偏心影响系数为：,-,偏心影响系数，对矩形截面可算得,2024/11/17,10,2.,偏心受压长柱,砌体受压构件的长柱多为中长柱，即破坏属于材料破坏。但要,考虑纵向弯曲,的影响,即考虑由纵向弯曲影响产生的附加偏心矩 ，由,考虑高厚比 和轴向力偏心矩 对受压构件承载力的影响系数,可表达为：,则偏心受压长柱的承载力可表达为：,3.1,受压构件的承载力计算,3.1,受压构件的承载力计算,2考虑砌体弹塑性能,比照 和 ，说明考虑砌体的弹塑性性能，到达一样边缘压应力时荷载值要比按材料力学分析的大。,则,考虑砌体弹塑性性能的偏心,受压短柱的承载力,可表达为：,3.受压影响系数 的计算(表3.1至3.3,当 ，由式3.8可得：，对于,矩形截面，将上式代至3.8，有：,其中：,3.1,受压构件的承载力计算,式中,为与砂浆强度等级有关的系数；当砂浆强度等级,M5,时，,=0.0015,；当砂浆强度等级为,M2.5,时，,=0.002,；砂浆强度为,0,时，,=0.009,。,3.1.4,计算受压构件承载力的统一公式,1.,计算受压构件承载力的统一公式：,即可以表达为：,3.1,受压构件的承载力计算,：荷载设计值产生的轴向力,：影响系数，由表查出。由公式可知，越大，构件的承载力越大。,：砌体的抗压强度设计值,由表查出,：截面面积,2.公式适用范围：,矩形截面构件，当轴向力偏心方向的截面边长大于另一,方向的边长时，除按偏心受压计算外，还应对较小边长方向,按轴心受压承载力进展验算。,3.偏心距较大时的处理方法,当 时，可实行以下措施：,1增大截面尺寸，使y值增大。,2在梁端或屋架端部支承处设置带中心装置的垫块或带缺口的垫块，以减小偏心距。,3承受组合砖砌体构件，提高构件的承载力。,3.1,受压构件的承载力计算,截面重心到轴向力所在偏心方向截面边缘的距离,课堂练习,例3.1一轴心受压砖柱，截面尺寸为370mmX490mm，承受MU10烧结一般砖及M2.5混合砂浆砌筑，荷载引起的柱顶轴向压力设计值为N=155