High-Force-to-Volume Seismic Dissipators Embedded in a Jointed Precast Concrete Frame

Abstract

An experimental and computational study of an 80 percent scale precast concrete 3D beamcolumn joint subassembly designed with high force-to-volume (HF2V) dampers and damage-protected rocking connections is presented. A prestress system is implemented using high-alloy high-strength unbonded thread-bars through the beams and columns. The thread-bars are post-tensioned and supplemental energy dissipation is provided by internally mounted lead-extrusion (LE) dampers. A multi-level seismic performance assessment (MSPA) is conducted considering three performance objectives related to occupant protection and collapse prevention. First, bi-directional quasi-static cyclic tests characterise the specimen's performance. Results are used in a 3D nonlinear incremental dynamic analysis (IDA), to select critical earthquakes for further bi-directional experimental tests. Thus, quasi-earthquake displacement tests are performed using the computationally predicted seismic demands corresponding to these ground motions. Resulting damage to the specimen is negligible, and the specimen satisfies all performance objectives related to serviceability, life-safety, and collapse prevention. Suggested Reviewers:Opposed Reviewers : 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 1 HIGH-FORCE-TO-VOLUME SEISMIC DISSIPATORS EMBEDDED IN A JOINTED PRECAST CONCRETE FRAME ABSTRACTAn experimental and computational study of an 80 percent scale precast concrete 3Dbeam-column joint subassembly designed with high force-to-volume (HF2V) dampers and damage-protected rocking connections is presented. A prestress system is implemented using high-alloy high-strength unbonded thread-bars through the beams and columns. The threadbars are post-tensioned and supplemental energy dissipation is provided by internally mounted lead-extrusion dampers. A multi-level seismic performance assessment (MSPA) is conducted considering three performance objectives related to occupant protection and collapse prevention. First, bi-directional quasi-static cyclic tests characterise the specimen"s performance. Results are used in a 3D nonlinear incremental dynamic analysis (IDA), to select critical earthquakes for further bi-directional experimental tests. Thus, quasi-earthquake displacement tests are performed using the computationally predicted seismic demands corresponding to these ground motions. Resulting damage to the specimen is negligible, and the specimen satisfies all performance objectives related to serviceability, life-safety, and collapse prevention. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 2 KEYWORDSHigh force-to-volume damper, HF2V device, lead ex...

Characterizing Seismic Resiliency Using an Energy Dissipation-Recentering Correlation Diagram

“…For example, unbonded prestressed tendons have been designed to work in conjunction with concrete frames at beam-to-column connections to invoke a self-centering component response (e.g., Priestley and Tao 1993;Stanton et al 1997). Selfcentering systems have also been augmented with elements that dissipate energy, such as mild steel reinforcement, customized energy dissipating bars or steel plate dampers, or ductile steel braces (e.g., Palermo et al 2005;Tremblay et al 2008), or high force-to-volume damper-based energy dissipation devices that are either externally mounted on beam-column assemblies or embedded in precast concrete frames (Rodgers et al 2012). Selfcentering systems have also been augmented with elements that dissipate energy, such as mild steel reinforcement, customized energy dissipating bars or steel plate dampers, or ductile steel braces (e.g., Palermo et al 2005;Tremblay et al 2008), or high force-to-volume damper-based energy dissipation devices that are either externally mounted on beam-column assemblies or embedded in precast concrete frames (Rodgers et al 2012).…”

Experimental studies on cyclic performance of column base weak axis aligned asymmetric friction connection

“…Such low-damage structures may be achieved by providing sufficient strength for them to remain elastic or by appropriate use of seismic isolation, rocking, or other techniques. Research on low-damage construction in steel frame structures has concentrated on beam-to-column moment resisting joints [7,10,[13][14][15]17,21,25,29,30] and braces [5]. Some of these techniques have been used in real construction (E.g.…”

Experimental study of a self-centering prestressed concrete frame subassembly

“…Early form of dissipators provided energy dissipation through metallic yielding of mild steel bars grouted in ducts across the beam-to-column joints (''hybrid'' connection) [4], which was developed in the US-PRESSS Program (PREcast Seismic Structural System) [5]. Subsequent research on ''hybrid'' precast structural systems brought other forms of dissipators, including tension-only mild steel devices [6], external mounted mild steel devices [7,8], lead-based damping devices [9,10], and friction-based devices on the top and bottom surfaces of the beam ends [11]. More recently, Chou and Chen [12] conducted full-scale cyclic tests on a one-story two-bay post-tensioned reinforced concrete steel (RCS) frame subassembly with reduced flange plates and demonstrated the excellent self-centering capacity of the PT frames.…”