Types Of Structural Members Research Articles

Reuse System of Building Steel Structures - Structural Performance of Reusable Members and Practical Examples

Longevity, reuse and recycle can be effective in reducing environmental burden in the life cycle of building steel structures. Longevity is the most crucial element in reducing the environmental burden of building steel structures. Nevertheless, there are always a number of buildings that need to be demolished for physical, architectural, economic, and social reasons. When such building steel structures have been demolished in the past, their structural members have been scrapped for recycling. Steel, by nature, is the only type of structural member that can be fabricated. Even without special joints that facilitate demolition work, steel members can be reused after minor fabrication procedures such as cutting, drilling, and welding. In this paper we discuss structural performance of reusable members and practical examples using reusable members.

Study on the Seismic Behavior of Green High-Performance Fiber-Reinforced Cementitious Composites Column

“Strong column and weak beam” failure rarely occurred in the Wenchuan earthquake, and the reasons were analyzed in this paper. A new type of frame column is presented, i.e. green high-performance fiber-reinforced cementitious composites (GHPFRCC) column, and the seismic behaviors are discussed. And this new type of structural member is vital to improve the seismic capacity of the frame structure.

Reliability analysis of tested steel I-beams with web openings

This paper presents a reliability analysis of steel I-beams with rectangular web openings, based on a combination of the common probabilistic reliability methods, such as RSM, FORM and SORM and using data obtained from experimental tests performed at the Istanbul Technical University. A procedure is proposed to obtain the optimum design load that can be applied to this type of structural members, by taking into account specified target values of reliability indices for ultimate and serviceability limit states. The goal of the paper is to present an algorithm to obtain more realistic and economical design of beams and to demonstrate that it can be applied efficiently to steel I-beams with web openings. Finally, a sensitivity analysis is performed allowing to ranking the random variables according to their importance in the reliability analysis.

PREDICTION OF DAMAGE IN R/C SHEAR PANELS SUBJECTED TO REVERSED CYCLIC LOADING

In this paper, the damage prediction of shear-dominated reinforced concrete (RC) elements subjected to reversed cyclic shear is presented using an existing damage model. The damage model is primarily based on the monotonic energy dissipating capacity of structural elements before and after the application of reversed cyclic loading. Therefore, it could be universally applicable to different types of structural members, includeing shear-dominated RC members. The applicability of the damage model to shear-dominated RC members is assessed using the results from reversed cyclic shear load tests conducted earlier on eleven RC panels. First, the monotonic energy dissipating capacities of the panels before and after the application of reversed cyclic loading are estimated and employed in the damage model. Next, a detailed comparison between the analytically predicted damage and the observed damage from the experimental tests of the panels is performed throughout the loading history. Subsequently, the effects of two important parameters, the orientation and the percentage of reinforcement, on the damage of such shear-dominated panels are studied. The research results demonstrated that the analytically predicted damage is in reasonably good agreement with the observed damage throughout the entire loading history. Furthermore, the orientation and percentage of reinforcement is found to have considerable effect on the extent of damage.

屋上緑化における植栽形態別の気温緩和効果及び断熱について

In the summer of 2004, an experiment was conducted to assess the moderating effect associated with the planting of green plants on rooftops on the thermal environment of the rooms below. Comparisons were made using different plant types and a variety of associated thermal affects were compared. Temperatures were measured at several points in the vertical on the roof surface material, within the roofing material measurements were made in different types of structural members, within the ceiling, and just below the ceiling in the rooms below. Separate measurements were also made in zones created by arranging the plants in different configurations. Zones were compared by varying the amount of irrigation water and vegetation cover; zones covered by greenery were compared with zones of exposed roof surface. Temperatures were measured from August 16 to September 15. The results showed that, on the hottest day of summer day on record in Yokohama Japan, August 20, temperatures in the zones covered by greenery were moderated by 1 to 4°C in the vertical direction when compared to areas of exposed roof surface. The ground, or roofing, acted to cool the atmosphere for 249 hours in the exposed zones, and for 287 to 449 hours in the zones covered by vegetation. Furthermore, a temperature difference of 10°C in diurnal and nocturnal temperatures was observed between areas that were covered by vegetation and those that were exposed.

Nonlinear FE Solution for Thin-Walled Open-Section Composite Beams

In thin-walled open-section beams made of fiber-reinforced laminates, symmetric with respect to their midplane, the bending and torsion are coupled. For this type of structural members, a nonlinear finite-element (NLFE) analysis based on the updated Lagrangian formulation is developed to solve the problem, numerically. The solution could further be expanded for bifurcation and buckling type of problems in composites. The linear and geometric nonlinear stiffness matrices are presented. The displacements of simply supported and cantilever composite channels due to static concentrated loads, applied at the midspan and the end, respectively, are measured and compared with the NLFE solution. The experimental results are in good agreement with the results of the finite-element analysis.

A Proposal of Fracture Control Design Procedure

In order to make the fracture mechanics analysis readily applicable at design levels with efforts normally required in design for stress analysis, this paper proposes its simplified application procedure. The key point of this procedure is the estimation of the crack propagation path and K value from the stress analysis results on crackless model.The proposed crack path estimation criteria are based on the study of the relationship between the direction of principal stress in a flat plate as well as the K value when the crack reaches a normal crossing member and the crack propagation path. The proposal also includes simplified K value estimation methods by grouping actual forms of cracking into several typical patterns, so that the designer can estimate the K value for almost any type of structural members which he will face in his design. To verify the validity of the proposed procedure, the bottom transverse damage of a large tanker was analyzed for comparison with the actual cracks. The analysis results are consistent in explaining the actual damage phenomena and this procedure has been proved quite practical through examination of the design measures taken.

The Assembly of Large Structures in Space: An Evaluation of Hardware Configurations and Assembly Techniques through Neutral Buoyancy Simulation

The implementation of NASA's Space Transportation System (STS) presents the opportunity for the on-orbit assembly of structures which, before the advent of multi-launch missions, were not possible because of their physical size. This report presents the results of an eight-month effort in the investigation of assembly techniques and hardware configurations used in assembly of the basic tetrahedral cell by A7LB pressure-suited subjects in Marshall Space Flight Center's Neutral Bouyancy Simulator. Eleven subjects participated in assembly procedures which investigated two types of structural members and two configurations of attachment hardware. The assembly was accomplished through extra-vehicular activity (EVA) only, EVA with simulated manned maneuvering unit (MMU), and EVA with simulated MMU and simulated remote manipulator system (RMS). Assembly times as low as 10.20 minutes per tetrahedron were achieved.

Some Aspects of Stub-Girder Design (T.R. Higgins Award)

Much research effort has been devoted to studies of the strength and behavior of the many types of structural members and connections that are commonly used in steelframed buildings. The investigations have primarily focused on how to make the best use of the available materials, assuming that the end product would be safe, serviceable, and—as much as possible—economical structures. To that end significant advances have been made throughout the years, providing for an ever-improving quality of the work of the structural engineer. From his viewpoint, therefore, the attention of the researchers has been properly directed, because their studies have enabled him to perform his tasks better. It is readily recognized, however, that the structural aspects of most building projects form but part of the total construction package. The completed structure must provide adequate service to its users in all respects, covering structural performance as well as all of the electrical, mechanical and environmental requirements that must be satisfied. This is probably best achieved by a systems analysis of the project design, which requires extensive cooperation between all of the parties that are involved in the work. Thus, not only must the architect, the structural engineer and the general contractor work together as early as possible, but it is increasingly important that the other groups in the design team participate fully in all of the decision making processes. For a building this primarily refers to the mechanical and the electrical engineers, because many of the services that are planned by these professionals may influence the way the structure is designed and constructed.

Economy of High Strength Steel Structural Members

Several types of structural members are analyzed to determine how higher strength steels can be used to their greatest advantage; influence of yield stress, modulus of elasticity, and price on optimum proportioning of structural members; it is demonstrated that through optimum design, application of higher strength steels can lead to significant material-cost savings for lighter weight structures.