Safety In Large Buildings Research Articles

Assessment and simulation of evacuation in large railway stations

Evacuation systems in buildings are frequently assessed to improve emergency response processes. This paper proposes a method to evaluate the performance of different evacuation modes, and determine a rational mode for large railway stations. We developed a simulation for the evaluation of fire safety in large buildings based on an analytic hierarchy process (AHP) method. This approach includes AHP-based exploration and simulation-based refinement. We considered a typical railway station for validation, conducted a field survey to collect the data, and calculated the influencing factors based on expert opinion. The influencing factors were further processed based on the principles of a hierarchical model. The relative weights of the influencing factors were calculated through a series of pairwise comparisons using the AHP. Further, we applied factor refinement based on the evacuation simulations to determine the degree and status of influence of each factor. The influence of external factors was generally stronger than that of the internal factors. Among them, the building component characteristics and people’s physiological capabilities were the core of the evacuation assessment in large railway stations. Additionally, the exit width, seat layout, visibility, speed, and reaction capabilities were crucial to the evacuation process. The proposed method is practical as it demands limited computations to provide useful information, such as a priority ranking of each influencing factor, for the evaluation process.

Grouting Reinforcement of Large Building Foundation over Old Gob Areas: A Case Study in Huaibei Mining Area, China

There are more than 14,000 square kilometers of mining subsidence areas in China, most of which have been reclaimed for the construction of new buildings. In the past, few special measures were required for the foundations of small buildings above old gob areas. But a plan was created to construct a large office building 100 m in length, 90 m in width, and 100 m in height, above old gob areas in the Huaibei subsidence area. However, the results of exploration borehole data and borehole TV observation indicated a broken bedrock stratum and developmental fractures above the old gob areas, and thus, the space stabilities of the building foundation were poor. Therefore, grouting reinforcement measure was adopted for the old gob and foundation areas. And the grouting effect was examined using borehole TV observation and the water injection test, where the detection results of boreholes TV observation showed that the filling ratio of the stratum fracture was over 85%, and the stability of the foundation was obviously enhanced. In addition, we monitored the settlement of the foundation continuously for 930 days. The results show that the maximum cumulative subsidence was 15.3 mm and the maximum slope was 0.05 mm/m, which verifies that grouting reinforcement is feasible in terms of the safety of large buildings constructed over old gob areas using bedrock stratum grouting in the Huaibei subsidence area.

Briefing: William Fairbairn and the ‘suspended girder’

This briefing introduces the reprint of a classic paper presented to the Institution of Civil Engineers in April 1847 by William Fairbairn. A month earlier, Fairbairn had investigated the cause of a partial building collapse at Ancoats Mill in Manchester in which a mill worker had died. Contemporary newspaper reports on the accident and the inquest are used to put Fairbairn's paper into context. Some background is provided to Fairbairn's serious concerns about the safety of large buildings when not designed and built by competent persons. Much of the discussion at the Institution after presentation of the paper was taken up by the defence by leading railway engineers of the principle of the ‘suspended girder’, a cast iron beam strengthened with wrought iron trussing rods. Fairbairn blamed the mill building collapse mainly on the use of the suspended girder, which at the time was gaining popularity for railway bridges of longer span. The paper explains how events unfolded soon afterwards to prove Fairbairn right and his eminent contemporaries wrong.