Shock Absorption-isolation Tech Adopted to Upgrade Quake Prevention and Disaster Reduction Abilities- The Institute contracted design program of the manufacturing base of related intelligent equipment
On July 12th, an earthquake of magnitude 5.1 happened in Tangshan, sensed in Beijing Tianjin and Hebei Porvince, which was believed an aftershock of the 1976 earthquake.
Since the turn of the 20th century, the death toll of earthquakes in China accounts for 55% of the world’s total. Two of the earthquakes claiming 200,000-plus both happened in China. Among all strong quakes of the advanced countries, the death toll is only one tenth of that of developing countries thanks to the shock reduction techniques used in buildings.
Building shock isolation-absorption technique is a flexible anti-quake technique, focusing on isolation: a layer of a building is set as the shock-isolation layer to isolate the upward transmission of the quake energy to safeguard the building. The shock-absorption, based on consumption, lays damper device in weak places of buildings to reduce shock response of the main structure of buildings, much like the shock absorbors of cars.
At present, China is developing at full speed economically and socially, which calls for public safety in terms of quake-disaster prevention and reduction, triggering a significant and immediate demand for research and application of related technique.
Plan and Design of Construction Map
The manufacturing base of intelligent shock absorption-isolation equipment is where the research building is seated that belongs to the Zhenan Shock Absorption-Isolation Company Limited of Hebei Province. The Institute’s Municipal Design Center contracted the program of the plan and construction map design. The base is located in the Beijing-Tangshan Intelligence Harbor of the High-tech Area. The quake fortification is set at 8 on the Richter scale. The designed peak value of basic seismic acceleration is 0.2g.The seismic grouping is the second, the site is II and the site characteristic period 0.4s. The building is in the form of frame construction,with five storeys, 21.95m in height, 20.24m in width ( a height-width ratio of 1.08).The construction is Type II of standard quake prevention, Etabs and PKPMV4.3 software used for analysis of the absorption and isolation.
Damping bearing arrangement: the bearings are set on top of the basement pillars with 34 plastic shock isolation bearings with a 0.016 ratio of yield to weight.
Damper arrangement: 11 buckling restrained braces, 3 viscous dampers, 2 friction dampers, 4 metal yield dampers, 1 viscous damper wall and 2 visco-elastic dampers.
Principal structural stiffness is upgraded via application of shock reduction and isolation and the damper ratio is increased for the principal structure, thus bettering the anti-shock ability of the structure.
Health Monitoring System for Buildings (Shock Absorption and Isolation)
Based on the theory that deformation first starts in flexible shock absorption and isolation device and by implanting micro sensors in the constructions ( with laminated rubber bearings) with shock absorption and isolation, the system monitors the working status and the vertical stress in typhoons and quakes, horizontal movements, and changes of seismic acceleration in order to respond to the stressed conditions and deformation status and pool the monitored data so as to reflect the structural health status of the buildings involved and build up data relays and terminals. Data bank is quickly formed via real-time monitoring, transmission, analysis and display. The monitoring, due to low cost, is applicable to all buildings with shock absorption and isolation.
On the afternoon of July 11th, technicians replaced the two ordinary shock isolation bearings, put upon early construction, with two rubber shock isolation bearings of implanted sensors. After this, a health monitoring system can be easily built up for such purposes: 1. supplying a platform for long-term and orderly monitoring, patrol inspection and maintenance of the buildings with shock absorption and isolation as well as digitized and IT-based archives of such structures; 2.spotting dangerous conditions, as early as possible, that emerge in the said structures so as to address them timely to ensure safety; 3. facilitating partial or wholesale application and development tendency of such structures to support data and information for maintenance decisions; 4. data results can be used in display for users’ search, scientific research and quick diagnosing of the health situation and supplying decision basis for governments in assessing and responding to disasters by virtue of such big data and buildings with shock absorption and isolation.