Dynamics of structures

Minimum Design Loads for Buildings and Other Structures provides requirements for general structural design and includes means for determining dead, live, soil, flood, wind, snow, rain, atmospheric ice, and earthquake loads, as well as their combinations, which are suitable for inclusion in building codes and other documents. This Standard, a revision of ASCE/SEI 7-05, offers a complete update and reorganization of the wind load provisions, expanding them from one chapter into six. The Standard contains new ultimate event wind maps with corresponding reductions in load factors, so that the loads are not affected, and updates the seismic loads with new risk-targeted seismic maps. The snow, live, and atmospheric icing provisions are updated as well. In addition, the Standard includes a detailed Commentary with explanatory and supplementary information designed to assist building code committees and regulatory authorities. Standard ASCE/SEI 7 is an integral part of building codes in the United States. Many of the load provisions are substantially adopted by reference in the International Building Code and the NFPA 5000 Building Construction and Safety Code. Structural engineers, architects, and those engaged in preparing and administering local building codes will find this Standard an essential reference in their practice. Note: New orders are fulfilled from the second printing, which incorporates the errata to the first printing.

Minimum Design Loads for Buildings and Other Structures

Seismic Rehabilitation of Existing Buildings

SUMMARY
In this study, we propose a new seismic control device, tuned viscous mass damper (TVMD), for building systems. We give a detailed description of an apparent mass amplifier using a ball-screw mechanism, which is one of the most important components for realizing the new device. We also derive a closed-form solution of an optimum seismic control design for a single-degree-of-freedom structure subjected to harmonic excitation. The performance of the new device is compared with those of the conventional viscous damper and viscous mass damper systems. The vibration control system using the TVMD is shown to be the most effective for linear structural systems with dampers having the same additional damping coefficient. The effectiveness of the TVMD for seismic excitation is verified by analyses and shake table tests with a small-scale TVMD. Copyright © 2011 John Wiley & Sons, Ltd.

Seismic control of single-degree-of-freedom structure using tuned viscous mass damper

An analytical method for developing a theoretical load-settlement curve for axially loaded piles in clay is presented. The method is based on the correlation of the ratio of load transfer to soil shear strength as a function of pile movement. The results of studies of field tests of instrumented piles and laboratory tests of small piles in clay are used to obtain the desired correlation. The correlation is presented in the form of a family of curves that are obtained when the ratios of load transfer to soil shear strength versus pile movement are plotted as a function of depth. The validity of the family of correlation curves is checked by comparing computed and actual load-settlement curves for some typical field tests. Results obtained by this method indicate that the method may be used effectively to determine load-carrying capacity for axially loaded piles in clay.

Closure to “Load Transfer for Axially Loaded Piles in Clay”

Assessment of progressive collapse-resisting capacity of steel moment frames

Behavior and design of structures with buckling-restrained braces

Experiments were carried out to investigate the progressive collapse-resisting capacity of reinforced concrete beam–column sub-assemblages designed with and without seismic load. The two-span sub-assemblages were designed as part of five- and eight-storey reinforced concrete moment-resisting frames. The exterior columns of the right-hand girders were designed to be 1·5 times larger in size than the middle columns to take into account continuation of the girder. A monotonically increasing load was applied at the middle column of the specimens and force–displacement relationships were plotted. It was observed that the non-seismically designed specimen failed by crushing of concrete at the exterior column–girder joint of the left-hand girder before catenary action was activated. However, the force–displacement relationship of the specimen designed for seismic load kept increasing after fracture of the girder lower rebars near the middle column due to the catenary force of the upper rebars. Based on the test ...

Jinkoo Kim

Papers

Assessment of progressive collapse-resisting capacity of steel moment frames

Behavior and design of structures with buckling-restrained braces

Progressive collapse-resisting capacity of RC beam–column sub-assemblage

Energy-based seismic design of buckling-restrained braced frames using hysteretic energy spectrum

Response modification factors of chevron-braced frames