Search

The study presents a possible innovative use of cement fiber boards (CFBs) reinforced with cellulose fibers for construction of an interior prefabricated staircase. Regarding the unusual use of traditional material that was used in all bearing elements of the staircase, a numerical simulation with the use of a material model SBETA was carried out and, subsequently, multiple experimental static loading was applied. In order to carry out experimental testing of static load capacity, a full-scale experiment method was chosen and performed on a real staircase structure for family houses. The full-scale experiment is considered the most precise method to test structures or material behavior. The obtained results show that the designed and tested staircase structure of CFBs is able to meet the requirements of technical standards related to static loading of staircases. The load test confirmed the potential use of cement fiber boards produced by the Hatschek process for real bearing structures under static loading.

A rubber isolation bearing installed in a staircase (RBS) was proposed to mitigate seismic damages to the component of staircases and improve their seismic performance. A series of quasi-static tests performed with respect to the horizontal and vertical mechanical properties of RBS as well as the numerical modelling were verified with experimental results. Next, the finite element models of typical types of reinforced concrete frames (without stairs, with cast-in-place reinforced concrete stairs, and with RBS stairs) were established. The modal dynamic and non-linear elasto-plastic analyses of system-level building models were herein conducted, respectively. The effect of the RBS on the dynamic response of the whole structure and the mechanical performance of stair components was revealed. The analysis results indicated that the RBS provided the desired floor-to-floor relative drift and effectively isolate the seismic action from the stair flight. Therefore, the presence of RBS can effectively mitigate the influence of a staircase on the entire building’s structure, weaken the diagonal strut effect of flights, and reduce the inner forces of staircase components.

In this work, we conducted downward evacuation experiments in four types of staircases under various smoke visibility conditions of the naked eye, wearing sunglass and wearing eyeshades. Ten male and ten female college students were recruited to conduct the evacuation as a single male, single female, two males supporting one another, two females supporting one another and one male carrying another on his back. The evacuation time on each floor was recorded. The corresponding evacuation models were established by Pathfinder and verified against the test data. The effects of evacuation crowd density and response time considering gender factors on the evacuation time were simulated using the models. The results show that under the experimental condition of low visibility, the curve of evacuation time presents a stable state, whose change with the increase in the floors is not obvious. The increase in the evacuation time under different visibility indicates that males have better adaptability to the environment than females. The curves of SSP (straight running stairs with platform) and DSS (double split parallel stairs) are smoother than those of DPS (double running parallel stairs) and CS (corner stairs), indicating less pressure and less congestion during evacuation. During the emergency evacuation, the crowd pressure on the platform of the staircases is small. The front section of the flight and the corner part of the staircases are prone to congestion during evacuation. Under the influence of gender factors, since the response time of males is longer than that of females, the smaller the proportion of males, the smaller the time growth rate considering the reaction time. With the increase in crowd density, the effect of response time on total evacuation time becomes smaller.