58. VISCOUS-DAMPER WITH MOTION AMPLIFICATION DEVICE FOR HIGH RISE BUILDING APPLICATIONS
Adding damping by the use of various damping devices has become an accepted method to reduce wind induced vibrations in tall buildings. An interesting example of a 39 story office tower is presented where large projected accelerations are the result of vortex shedding of an adjacent existing 52-story building. Viscous dampers and a toggle brace type motion amplification system are used to suppress the anticipated accelerations. A description of the damping system and its analytical simulation are discussed. This paper includes a nonlinear analysis of the tower, with time history forcing functions derived from wind tunnel testing. Cost data for the damper system is also presented.
48. Arrowhead Regional Medical Center
This article describes every aspect of the design and construction of the Arrowhead Regional Medical Center, including the use of base isolators and viscous dampers to insure continuous operation even after a major seismic event. The article even includes many of the financial aspects of this huge project.
46. DESIGN OF STEEL PYRAMID USING FLUID VISCOUS DAMPERS WITH MOMENT FRAMES
The Eleven story 450,000 ft2 pyramid shaped office building described in this article was one of the first new buildings in the United States to use Seismic Dampers. This National Headquarters for a financial institution is located in West Sacramento, CA. The basic lateral force resisting system of the building consists of steel moment frames. In addition, approximately 15% of critical damping was provided using Fluid Viscous Dampers (FVD) in order to reduce displacement and acceleration. The steel moment frames were designed to remain well below the yield strength, and the story drift ratio was limited to 0.005 to protect the welded moment connections for the Design Basis Earthquake (DBE). Earthquake performance, cost effectiveness, and architectural requirements were the primary concerns in designing this building.
43. PRE-QUALIFICATION TESTING OF VISCOUS DAMPERS FOR THE GOLDEN GATE BRIDGE SEISMIC REHABILITATION PROJECT
This report presents the results of the testing of a viscous damping device provided to the Earthquake Engineering Research Center (EERC) of the University of California at Berkeley for pre-qualification testing as part of the seismic rehabilitation of the Golden Gate Bridge. In all, four different viscous dampers from four different manufacturers were tested in the prequalification program. This report presents the test results for the damper denoted Damper C. The test results for the other three dampers, Dampers A, B, and D, are presented in separate reports. Conclusions were that Damper C performed consistently and well throughout the entire testing/pre-qualification program. This report also includes a complete specification for production dampers for this project.
35. SEISMIC REHABILITATION OF A HISTORIC NON-DUCTILE SOFT STORY CONCRETE STRUCTURE USING FLUID VISCOUS DAMPERS
Hotel Woodland is one of the first structures in North America to be seismically retrofitted using viscous dampers. This four story 1927 vintage Historical Landmark reinforced concrete building is located in Woodland, California. It was essential to improve the earthquake response performance of the building and minimize cost while maintaining the historical appearance of the building. This paper presents the processes and decisions regarding retrofit criteria and design procedure for earthquake demand, building response performance, historical interests, and economic considerations.
19. SEISMIC DAMAGE CONTROL WITH PASSIVE ENERGY DEVICES: A CASE STUDY
This paper presents a theoretical case study of the effectiveness of supplemental passive damping to reduce structural response to seismic excitation. A six story special moment resistant reinforced concrete frame is studied with and without the aid of supplemental dampers. Response predictions are presented for each case. Fluid dampers proved to be a very cost effective way to significantly reduce the seismic response of the building investigated. Preliminary cost estimates indicate that positive damage control can be economically achieved.
17. SAN BERNARDINO COUNTY MEDICAL CENTER REPLACEMENT PROJECT TECHNICAL SPECIFICATIONS
This specification covers the set of 186 fluid viscous dampers used on the five buildings of the new San Bernardino County Medical Center located in Colton, California. Three major faults are close to this location. The dampers operate in parallel with elastomeric base isolators, and reduce the required isolator stroke from +/- 48 inches to +/- 22 inches. This specification is very detailed and includes testing requirements.
16. ROCKWELL VISCOUS DAMPER SPECIFICATIONS
This specification covers the set of ten linear fluid viscous dampers along with their mounting brackets and pins for the Rockwell Building located at Jamboree Road and Birch in Newport Beach, California. These dampers provide an output force in either tension of compression that is directly proportional to the relative velocity between the two ends of the dampers. The damper output force varies only with velocity and does not change with damper stroke position or orientation angle. The function of the dampers is to absorb earthquake energy, thereby reducing the amount the building moves when an earthquake occurs.
10. INVESTIGATION OF LIGHT POLE BASE INTEGRITY – RICH STADIUM
Light poles at Rich Stadium in Orchard Park, N.Y., were showing incipient failure of their hold-down bolts, due to wind excitation. This paper describes the measures used to alleviate this problem, including the addition of viscous dampers between the stadium structure and a point around one third up on the light poles.
9. GOLDEN GATE BRIDGE SEISMIC RETROFIT DESIGN SUSPENSION BRIDGE STRATEGY TECHNICAL REQUIREMENTS FOR DAMPERS by T-Y-Lin International
This specification, prepared jointly by TY Lin and Imbsen Associates, describes the requirements for the viscous dampers to be used in the retrofit of the Golden Gate Bridge. The specification includes wind excitation as well as seismic, and also describes testing requirements.