Stability And Measures For The Wall Limb With Rectangular Section Of Staircase Outer Wall Of The Shear Wall Structure

In order to meet the requirements of the building’s use function,the outer wall of stairwells with high-rise shear wall structure is often designed with a wall limb with rectangular section.As the staircase is the only escape route during an earthquake,it is particularly important to ensure that out-of-plane destabilization does not occur during the earthquake when wall limbs with rectangular section of the outer wall of the stairwell are under the influence of earthquakes.The main characteristics of shear wall with rectangular section are as follows:there are windows near the staircase board,the wall limbs are connected only by coupling beams with the wall two sides;the wall is preceded by the staircase in construction,there is no connection between the ladder plate and the wall;in the case where the stair beam is arranged above the connecting beam connected to the wall limb,the stair beam is also not connected to the wall limb;Therefore,there is no support outside the plane of the glyph wall limb and the calculated length is large,and there is a problem with stability.The wall stability check method given in the existing specifications does not consider the weight of the wall,but only applies to the situation where the wall top acts on the concentrated force.Based on the stability theory,this paper uses the energy method to derive the formulae for checking the out-of-plane stability of the wall limb.The formula can consider three kinds of working conditions,namely the action of self-weight,self-weight and wind load,and the combined action of self-weight,wind load and earthquake.Then ABAQUS software was used to analyze the eigenvalues of the wall limb.The analysis results were consistent with the formula.Finally,this paper selects engineering examples and carries out checking calculations.It points out that there is a problem of out-of-plane stability for the wall limb with rectangular section and proposes corresponding treatment suggestions.After analysis,this paper draws the following conclusions:(1)The formula proposed for checking the out-of-plane stability of wall limb with rectangular section is correct.It can be considered under the action of self-weight,under the combined effect of its own weight and wind load,and under the combined effect of its own weight,wind load and earthquake.(2)Under the action of earthquake,wall limb with rectangular section of the shear wall structure may have the possibility of out-of-plane instability;(3)The addition of reinforced concrete flanges or air shafts on the wall limb can improve the stability of it,but they cannot fully guarantee the stability;(4)Stretching the risers into the wall limb can make the ladder board served as an out-of-the-wall support for the stability of the wall limb.