Reliability Evaluation and Functional Optimization of Urban Earthquake Resistance and Disaster Prevention System

Xu Xingxing, Wang Wei* and Ma Donghui*

Based on the theory of reliability and combined with the fuzzy fault tree analysis method, a new method of evaluation and functional optimization of earthquake resistance and disaster prevention system is proposed. Based on the establishment of fault tree of the system, aiming at the shortcomings of not considering the fuzziness and failure dependency in the traditional fault tree analysis, the reliability vector and the triangular fuzzy number method are used to evaluate the urban seismic capacity.

At the same time, the impact of the failure dependency between events on the reliability of the fault tree system is also considered. Combined with the theory of reliability allocation, the optimized redistribution quantitative models of the reliability for every unit in the system are established, which provides a complete theoretical method for the evaluation and optimization of urban earthquake resistance capacity.

Through an example, the calculation process of evaluation and the optimized redistribution of the reliability are described in detail. The research shows that this method is more general, for it can overcome the assumption in traditional method that the failure of each unit is random and independent with each other. Also, it can find out the weak links and achieve the optimal allocation of the system.

Full Text

Flood Management in Hirakud Reservoir using Particle Swarm Optimization

Rath Ashutosh, Samantaray Sandeep* and Swain Prakash Chandra

This work proposed particle swarm optimization (PSO) a meta-heuristic technique to develop operating policies for flood control in Hirakud multi-purpose reservoir, Sambalpur, Odisha, India. The flood control reservoir is designed to moderate flood and not to conserve water. Real time reservoir operation is a challenging task. The reservoir releases are influenced by the inflows and the reservoir storage levels. The present research develops effective reservoir operation policies by using optimization technique and demonstrates the utility for practical applications. The inflows into the Hirakud reservoir are highly uncertain, which often induce lot of uncertainty in release policies. Therefore, it requires developing operation policies at different exceedance probabilities of inflows to assess the associated risks and developing real time reservoir operation models to facilitate easiness in reservoir operation system. Mostly such problems involve non-linear optimization to find a feasible solution as it involves good quantities of equality and inequality constraints.

In this study, it is intended to test the usefulness of PSO in solving such type of problems. To formulate the PSO model for reservoir operation, the problem is approached by considering a finite time series of inflows, classifying the reservoir volume into several class intervals and determining the reservoir release for each period with respect to a predefined optimality criterion. The multiple objectives comprise of minimizing flood risks, minimizing irrigation deficits and maximizing hydropower production in that order of priority. The developed model is applied for monthly operation. The results of the models indicate that PSO model performs better in flood control restrictions.

Full Text

Hazard-centric Evacuation Experiments - A Study on Occupant Responses to Earthquake Alarm

Illiyas Faisel T.*, Mani Shibu K. and Babu Naveen

Behavior of individuals during the evacuation process is a principal factor in determining the success of an evacuation. Individual response to an earthquake evacuation alarm has been studied by comparing the results of two evacuation trials. Evacuation trials at familiar environment and unfamiliar environment were conducted with two groups of student participants of same age group. Occupant response during and after evacuation alarm, pre-movement time of occupants and attachment of individuals to familiar faces have been studied for familiar and unfamiliar environment. A difference has been found in the evacuation time and velocity between female and male participants.

The affiliation behavior to close friends was quite evident in the evacuation experiments. Togetherness while evacuation was found to be preferred by most of the evacuees. Clogging and arching of evacuees have been observed in front of the exit doors which resulted in delayed evacuation. Occupants at familiar environment used available means of egress comfortably and evacuated faster than the occupants of unfamiliar environment. The tendency of people to follow others during evacuation and attempting to exit through the door from which they might have entered in the building would make the evacuation competitive and slower.

Full Text

Parametric Study on Effect of Wind on Geometrical Configurations of RC Space Frames

Markandeya Raju P.*, Madisetti Pavan Kumar and Sahithichandra B.

Man’s quest towards variety in architecture is one of the many challenges faced by Structural Engineers today. In this context there is a need to study the effect of geometrical configuration of RC frames on their performance. The objective of this research is to study (G+5) multi-storey RC frames of 4 different shapes of buildings (i.e. Circular, Rectangular, Square and Triangular) in plan.

Further, for rectangular shape building, different aspect ratios (L/B = 1.25, 1.5, 1.75 and 2.00) were considered as it is not rational to simply compare RC frame of one aspect ratio with other shapes of buildings. The structures were analyzed for 6 different basic wind speeds that are considered according to IS 875:2015 (PART III).

The study is aimed at comparing lateral displacements and quantity of steel required for different shapes of buildings for all the considered basic wind speeds keeping the number of columns and concrete quantity constant. From this study, it can be concluded that Space Frame that is rectangular in plan with 1.25 aspect ratio (SFR (1.25)) is found to undergo minimum lateral displacement in X-Direction compared to other shaped buildings for all basic wind speeds considered in this study.

For all basic wind speeds, maximum X and Z displacements were observed to be highest for space frame with triangular plan. The space frame with rectangular plan with 1.75 aspect ratio [SFR (1.75)] is observed to require minimum amount of steel compared to other frames followed by Space Frame with Square Plan (SFS), Space Frame with Rectangular Plan with 1.25 aspect Ratio [SFR (1.25)], Space Frame with Rectangular Plan with 1.50 aspect Ratio [SFR (1.50)], Space Frame with Rectangular Plan with 2.00 aspect Ratio [SFR (2.00)], Space Frame with Circular Plan (SFC) and Space Frame with Triangular Plan (SFT).

Full Text

Distribution of land subsidence in Shandong province and its potential disasters

Huai Baojuan, Wang Yetang* and Sun Weijun

Land subsidence has become one of the most prominent geological environmental problems affecting the sustainable development of economy and society in Shandong province. The results indicated that Dezhou, Dongying, Binzhou, Weifang (part), Liaocheng, Zibo (part), Jinan (part), Heze (part) and Jining (part) have suffered different degrees of land subsidence and Dezhou is the most serious.

It is imperative to improve the monitoring network of land subsidence and effectively control groundwater, coal and petroleum resources exploitation in these cities.

Full Text