Structural Control Using LRB in Irregular Building

Earthquakes are measure as one of all nature’s greatest hazards; throughout the historic time they need to cause important loss of life and severe harm to property, particularly to man-made structures. On the opposite hand, earthquakes offer architects and engineers a variety of vital criteria foreign to the traditional style method. during this analysis paper study, base isolation as an associate degree earthquake resisting style technique was used that well dissociate a construction from its substructure and increase flexibility resisting on the bottom vibration areas by providing the isolators. Lead rubber bearing (LRB) isolator could be a passive structural vibration management technique. during this analysis study, unstable behavior of irregularity building in the simple model, re-entrant corner plan irregular model, mass irregular model, and stiffness irregular model are measure configurations with varied frame sections with and while not LRB base isolation was analyzed for the comparative analysis on the idea of base shear, storey shear, stoery displacement, storey drift and storey acceleration with 3 earthquake information, first is Bhuj earthquake, second is Kobe Japan earthquake, and third is Loma Prieta earthquake analysis is done by E-TABS 18.0.20software. Non-linear time history analysis and for design purpose of a base-isolated system and for seismic design of isolated structure consistent with IS 1893 (part 1):2016 and UBC 1997.

Effectiveness of electromagnetic monitoring in studying earthquakes

Numerous researches conducted in connection with the study of earthquakes have shown that electromagnetic monitoring studies have led to some important results. From the Loma Prieta earthquake to the Guam earthquake, electromagnetic monitoring studies led to significant results. Since then, there have been numerous reports of possible elect-romagnetic precursors to earthquakes, some of which have involved frequencies covered by ELF/VLF (10—32 kHz) monitoring system Fraser-Smith et al. [1990]. Sometime later, they retrieved and started processing their ULF data. They had less reason to expect electromagnetic precursors in this latter data, because previous reports of precursory signals at frequencies below the ELF/VLF range have, with few exceptions, involved frequencies either below or predominantly below their ULF range (0.01—10 Hz) of operation. They found out that ELF/VLF data do not appear to show precursory activity, whereas ULF data contain a number of anomalous features that may prove to be earthquake precursors. The lack of observation of precursory ELF/VLF noise so close to the epicenters of several mode-rate to moderately-large earthquakes showed that ELF/VLF noise need not be a strong or obvious feature of every earthquake, as Fraser-Smith et al. [1990] reported in their paper. At present, numerous studies have been conducted in this area and researches are being improved. From my experience as a young researcher, it became clear that electromagnetic monitoring research is necessary, and that more important and significant results can be achieved if continuous research is conducted in a certain area. Thus, these studies may play a significant role in the detection of earthquake precursors.

The Loma Prieta earthquake and the cost of voting in the 1989 San Francisco municipal election: Evidence from a natural experiment

On October 17, 1989, the Loma Prieta earthquake struck the central coast of California. Three weeks later, on November 7, 1989, San Francisco held a municipal election. A dozen polling places had been destroyed or were otherwise inaccessible to the public due to the earthquake, so new polling places were selected for the affected precincts in the days leading up to the election. This case represents a credible natural experiment examining how changes in the costs of voting affect political participation, with the “as-if” random assignment of voters to the treatment group determined by earthquake damage to individual buildings rather than election administration decisions which could conceivably be related to turnout, such as precinct consolidation or the location of precinct boundaries. We use a difference-in-differences design, with the difference in turnout between the 1987 and 1989 municipal elections as the outcome variable. We find that voter turnout was 2.9 [5.1, 0.6] percentage points lower in precincts in which the polling place was relocated due to earthquake damage as compared to precincts that kept their original polling place.

Performance Evaluation of Tall Buildings using Optimized Tuned Mass Damper

This study investigates the performance of tall buildings using tuned mass damper (TMD) under dynamic loads such as harmonic loads, and the Loma Prieta Earthquake 1989 data. The numerical investigations are performed by considering a sixteen-storied dynamical system. To do this end, the aforementioned system is considered to be uncontrolled (meaning no damper is used) and a controlled case is assumed where a TMD is placed on the top floor. TMD performance mainly relies on the set of parameters (mass ratio, damping ratio, and stiffness). In reality, the tuning process of those parameters take serious effort and gets worse with the complicacy of the structure. Hence to obtain better performance of the TMD the damping ratio and the frequency of the TMD are optimized by using unconstrained derivative-free method. Finally, the uncontrolled and controlled performance of the sixteen-storied structure has been evaluated and compared. The results show that the dynamical response of the studied problem can be reduced significantly via the use of optimized parameters.

EVALUASI KINERJA STRUKTUR JEMBATAN PELENGKUNG AKIBAT BEBAN GEMPA DENGAN ANALISIS RIWAYAT WAKTU

The behavior of the arch bridge structure has its own peculiarities in distributing loading. The curved shape of the structure allows the structure's own weight to be transferred to the foundation as the normal compressive force without bending. the load is transferred through the semicircular structure to the abutments on either side. The curved (semicircular) design will naturally shift the load received by the floor of the bridge vehicle towards the abutment which keeps both sides of the bridge from moving sideways. Earthquake is a dominant horizontal cyclic loading of a structure. The performance of bridge structures due to the effects of earthquake loading is an important aspect that needs to be taken into account in designing and evaluating the bridge structure. The method used in this study is time history analysis. This article aims to evaluate the performance of arch bridge structures due to earthquake loads by using time-history analysis method. The results of the structure performance show that. The performance of the bridge due to the loading of the Loma prieta earthquake is generated from the period scale that has been analyzed with the 10 second period of the first earthquake for each result. Based on the results of Midas analysis, the strongest location where the damage occurs is in the middle of the bridge road. At the coordinates of 19 the largest displacement is at joint 268 of 1.177169 mm and for U2 of 0.0194 mm and U3 of 31.763771 mm.

Structural Failure Analysis of Building E ITERA Due to The Pounding Effect with Non-Linear Time History

[EN] Lampung, a province where Institut Teknologi Sumatera (ITERA) is located, is an area that has a high level of seismicity. This research takes a case study of the Building E ITERA which has a dilatation building concept. Due to dilatation, inter-buildings have the risk of collisions because of earthquake loads. The purpose of this study is to determine the value of joint displacement in adjacent buildings when given a dynamic load of Time History and determine whether the adjacent buildings experience a pounding effect. A Time History earthquake load data that has been matched with the Lampung region response spectrum by software is applied to the model of Building E. Building E is modeled according to the as built drawing data and the results of field checking. Structure is analyzed using software. The results of the study showed that the structure of the Building E which was loaded by Loma Prieta earthquake that has been matched would experience inter-building collisions. Further research using earthquake record data taken in areas within certain radius from ITERA is need to be conducted to obtain more accurate results.