Papers by Keyword: Roof Structure

Abstract: This paper is concerned with auto-body frames and roof structures against rollover motion which could take place frequently with TWVs compared to FWVs because of the major difference of the loading between the two motions. Topology optimization is utilized for conceptual design and preliminary design of the roof structure for various loading conditions. The roof structure for TWV consists of existing part of FWV and a new part called Cross-bar reinforcement. Although a test method for regulation of roof strength is with static loading, simulations are carried out for both static and dynamic cases. In the dynamic loading case, rate-dependency of a material needs to be considered for accurate results of FE analysis.

Abstract: With the resources exhaustion of medium-thick and thick coal seam, the mining technology of thin coal seam has attracted more attention. Due to the little working space for mining in thin coal seam, blasting mining and high-grade conventional mining are main mining methods that were used in thin coal seam. Taking the 17^th coal seam of Liyan mine as an example, in this paper we analyze the roof structure of the lower thin coal seam under the goaf of the upper coal seam. The fully mechanized mining equipment is selected on the basis of the new roof structure and applied in field. Finally, safe and efficient mining is achieved by improving the adaptability of the equipment.

Abstract: The constraints of resources and environment in China are more and more intense. The 12th Five-Year Plan requires that energy saving must be considered in the architectural design. Liangshan has special climate and sunshine. Therefore, the Government of Liangshan requires that building energy saving must be started from the stage of architectural design. Building energy efficiency must be considered from several aspects, such as architectural layout, wall structure, windows and doors, roof structure, external sun-shading, and construction materials.

Abstract: Beside seismic activity climate changes, reflecting in extreme events such as heat and cold waves, storms and floods, presents the main natural hazards. Although predicting events perimeter is not trivial, the vulnerabilities of society emphasizing built environment should be at least critically estimated and re-estimated, especially after the occurrence of such event. Many strong thunderstorms causing huge damage to agriculture and to build environment occurred in recent summers. Meteorologists concluded that summer storms especially those ones in July and August 2008 were very intense and affected many Slovenian regions. Extensive damage to buildings rose up questions about possible causes: bad construction practice, use of inappropriate materials, deficient maintenance and inadequate building regulation relating to loads. Some experts also claimed that additional material and product characteristics should be tested /defined to prevent extensive damage, like hail resistance for example. Slovenian National Building and Civil Engineering Institute (ZAG) tried to answer to these questions in a special research project, financed by Slovenian Ministry for Environment and Spatial Planning (MOP).

Abstract: Timisoara is an important city situated in the westernmost corner of Romania. Its historic core was until late XIX^th century a heavily defended citadel. The Great Synagogue in the Citadel, inaugurated by the Emperor Franz Josef I, is one of the most spectacular buildings of the city. A centrally shaped and domed building, enveloped in “moorish-andalusian” decorated façade, stands out for both the civic dignity of the newly emancipated Jewish community (1865), and its desire to integrate in the modern society. The beautifully ornamented massive brick building, covered by a central skylighted dome and surrounded by vaulted aisles also contains two exceptional wooden structures: the interior balconies including the orgue balcony and the roof structure over the vaults. Both are functional as well as ornamental, structurally and geometrically sophisticated and displaying high levels of craftsmanship. The ongoing project for the restoration of the Synagogue and its conversion into an auditorium revealed the complexities of the wooden structures – the lightweight and delicate balconies were able to sustain hundreds of worshippers for more than a century: the complex roofing system, stretched between the exterior tympans, the skylight of the dome and the exterior profile of the vaults, display elegance and minimalism. Both structures withstood the test of time, neglect and constant seismic activities. Maintaining these structures according to contemporary safety and risk management standards proved to be both a challenging and a rewarding opportunity.

Abstract: Wind tunnel tests of 1:100 rigid model of fish-shaped roof structures were carried out. The mean, fluctuating (RMS) and peak pressure coefficients, the local shape coefficient distributions on fish-shaped roofs were presented and discussed. It was found that negative pressures (suctions) occurred on the most areas on the roofs, and high negative pressure coefficients occurred on the eaves and cantilevered roof parts. When wind flows blew along the corridors under the roofs, the flows enhanced suctions on the surfaces of the roofs, and the suctions on the lower surface were greater than those on the upper surfaces, positive pressures occurred on that area after superposition of wind actions on the two sides. The roof eaves and regions above the corridors experienced the worst RMS pressure coefficients and the worst minimum pressure coefficients. The distribution characteristics of the worst RMS and minimum pressure coefficients were found to be quite similar to those of the mean pressure coefficients. The results obtained from the experimental investigation are expected to be useful in the wind-resistant design of complex roof structures in typhoon-prone regions.

Abstract: Based on the structural characters of roof in fully mechanized top coal caving, mechanical analysis, mechanical calculation and simulation experiment were used to explore the particularity of roof structure in fully mechanized top coal caving. The simplified model of roof structure was built in final. The results shown that, during the mining by fully mechanized top coal caving, dynamic balance arch structure was formed by the roof and surrounding rock in working face. In the same time, multi span beam structure was formed in the tendency direction. The results of this paper would provide the theory basis for exploring the strata behavior regularity in further, and promote the safety in production of coal mining enterprises.

Abstract: An arch-truss roof structure with circular steel tube is applied to a gymnasium, which is supported by two three-dimensional trusses with square steel tubular, and the connections between arch-truss and spatial truss are set to hinged supports. Natural frequency and modes of this overall roof structure are analyzed, and time-procedure analysis is acted by applying ANSYS software. The analysis results demonstrate that this roof structure has larger stiffness, and its maximum node displacement under earthquake can meet the requirements.

Abstract: This paper deals with the issues involved during the design of a complex roof structure in the grand theater located at the city of Hangzhou, China. The complexity comes from the structural being of three reasons: long-span, complex structure and special figuration. To study the roof structure completely, researches on the mechanical properties of the structure are carried out in the paper. The nonlinear finite element method is used to analyze the geometrical nonlinear stability. Buckling and post-buckling analyses are performed to determine the load-carrying capacity of the perfect and imperfect roof structure. Meanwhile, the critical loads of the structure with different parameters are also discussed in this paper. It is shown that the effect of supporting stiffness originated from foundations and concrete structures to improve the critical load is evident. The buckling of the structure is a global collapse. With the temperature rises, the limited load-carrying capacity of the structure decreases obviously.

Abstract: Based on the theory of maximum likelihood estimation, a set of nonlinear equations is first derived for determination of parameters of Weibull distribution. To speed up convergence, an efficient algorithm is proposed for solving the parameters. Further, a large-span roof structure is taken to demonstrate the proposed method. It is proved that the responses of a nonlinear structure have non-Gaussian properties under the excitation of non-Gaussian stochastic wind pressure field. By Weibull distribution fitting, the maximum and minimum values of structural response with a certain assurance rate are computed, and the results are compared with those obtained from normal distribution.