The problem of inappropriate time-history waveforms due to gaps between wall and fluid particles in the boundary conditions of SPH method was solved by modeling the wall particles shifted by the ...smoothing length. Based on the verified method, a fluid analysis was performed where cubic buildings were aligned. As a result, the continuity of pilotis space in orthogonal direction to mainstream causes the concentration of the hydraulic force on the wall of the building located downstream direction of the piloti-type buildings. And the continuity of pilotis space in mainstream direction also keeps the level of water pressure over a distance.
Due to the 2017 Pohang earthquake, many low-rise piloti buildings suffered minor to severe damage. Low-rise piloti buildings in Korea are generally both vertically and horizontally irregular systems. ...The first floor is a weak and soft story, and the core wall is located at the corner or edge of the plan creating a horizontal irregularity. Furthermore, the damage investigation indicates that the insufficient amount of column hoops and poor detailing of reinforcement. It was presumed that the combination of soft story, torsional behavior and poor detailing brought brittle failure at the columns located at the furthest distance from the core. Such a brittle and irregular nature makes it difficult to predict damage with a HAZUS-type approach, which uses seismic fragility functions defined in terms of the spectral displacement and the capacity spectrum method based on pushover analyses. Comparison of pushover analysis results of piloti buildings indicated that location of peak and overall deformation capacity differed with the intensity of the torsional behavior and failure mode of the column. Therefore, this study aimed to develop an improved seismic fragility function for piloti buildings. To reflect the observed damage, the use of damage criteria based on member performance, including stress and strain, and spectral acceleration was proposed. Fragility functions for the piloti buildings were constructed by using three-dimensional incremental dynamic analyses. Damage estimates for piloti buildings in the target area that were obtained by using obtained fragility functions showed good correlations with damage survey data.
•New fragility function for brittle piloti buildings were developed.•Stress and strain instead of displacement were used for damage criteria.•Three dimensional analyses were used to account for torsional behavior.
Piloti-type reinforced concrete building structures have vertically irregular configurations composing a moment frame for parking spaces in the lower story and heavy-weight shear wall system for ...residential spaces in the upper stories. Due to these vertically irregular configurations, such building structures are governed by a soft-story mechanism, damage concentration on the first story. Since the 2017 Pohang earthquake led to severe damage to the piloti-type building structures on a regional level, a decision-making tool mitigating the seismic damage for future events is needed. This paper aimed to propose a rapid decision-making tool promptly estimating seismic damage with simple information and determining a retrofit scheme using a pre-developed extensive database, i.e., multi-dimensional structural parameter surfaces. The multi-dimensional surfaces were created using a simplified modeling approach with five structural parameters: period, strength ratio, and ductility controlling failure modes as the input, and peak inter-story drift ratio and demand-to-capacity ratio as the output. The proposed methodology was validated using a finite element model for the piloti-type building structure with a soft-story mechanism. The seismic responses detected from the multi-dimensional surfaces have a slight difference from those of the numerical model. Nevertheless, the rapid tool predicted a reasonable agreement with performance evaluation from the finite element simulation. In addition, the rapid tool provided feasible retrofit options to meet target performance using brief structural information. Due to its simplified process, the proposed tool can be implemented to the regional seismic assessment for the residential areas where the piloti-type building structures were highly concentrated.
•Seismic vulnerabilities to piloti-type buildings highly concentrated in urban areas due to their vertical irregularities.•Extensive database from simplified numerical models reproducing the seismic vulnerabilities of the piloti-type structures.•Development of a database-based tool for regional seismic damage assessment of the piloti-type buildings.•Validation of the proposed tool with finite element simulation of a vertically-irregular building structure.•Establishment of retrofit schemes for piloti-type building structures with brief structural information.
This research proposes a surrogate model to predict the seismic response of individual structural elements in structures whose inherent vertical and horizontal irregularities result in components ...with different seismic vulnerabilities. A frequency-based data-driven model was developed which predominantly uses the frequency spectrum of earthquakes as input data. The seismic responses of several structural components can be simultaneously generated as output using the proposed model. A comparison of structure fragility assessments obtained with a conventional approach, and the proposed Deep Learning-based approach, was conducted to verify the accuracy of the proposed method's prediction capability.
In Korean residential building, wall – piloti structures have been frequently used in the ground floor. For cost-effective design, a new wall – piloti structure where the walls are directly connected ...with the columns without transfer girder was suggested in the previous study. In this study, the proposed structure was applied to actual residential building. To verify the structure safety, structural monitoring and long-term behavior prediction was carried out. Strain gauge and displacement meters was installed to measure the strain of re-bars and the deflection of slab. During the construction period, in all wall – piloti structures, compressive strain was less than the allowable strain and relative deflection of slab satisfied the serviceability criteria. Further, in the long-term behavior, the maximum vertical strains of the re-bar were less than allowable strain under the service load condition.
A strength–ductility type seismic retrofit technique for soft first-story reinforced concrete (RC) buildings via adding wing-walls to the existing RC columns is called thick hybrid wall (THW) ...technique. In this technique, the additional wing-wall does not require longitudinal, transverse and anchor reinforcements; therefore, its construction is easy and cost-effective. In this study, THW technique was applied to an existing pilotis RC building in Okinawa. The objectives of this study were (1) to compare the advantages of THW and conventional retrofit techniques applied to this pilotis building, and (2) to assess the future retrofitting activities through this study.
This study investigated the seismic vulnerability of piloti-type bearing wall buildings supported by columns and walls on a weak first floor. Linear and nonlinear static analyses were performed to ...investigate the contributions of the columns and walls to lateral strength and stiffness, depending on torsional irregularity. The results show that the columns and walls were dominated by flexure and in-plane shear, respectively. Before yielding, the walls resisting in-plane shear mainly contributed to the stiffness and strength of the buildings; as shear cracking and yielding of the walls occurred, the contribution of the columns to the strength increased. Thus, during the inelastic behavior, the columns significantly contributed to the peak strength and ductility. Based on the results, design and detailing requirements for the columns and walls on a weak first floor were proposed. The validity of the proposed method was verified through nonlinear static and dynamic analyses. Keywords: nonlinear static analysis; piloti; seismic design; soft story; torsional irregularity; wall; weak story.
The piloti is one of the important design method of LingNan architecture to adapt to the climate, piloti space is an important space meet the communication between teachers and students. The ...three-dimensional non-hydrostatic climate model ENVI-met were applied to simulate differents of heights of piloti and proportion of piloti. Study the effect of different cases of piloti on campus cluster thermal environment.
The seismic performance of a concrete column retrofitted with an iron-based shape memory alloy (Fe-SMA) was evaluated under cyclic loading. In addition to structural behavior, internal damage was ...monitored using an ultrasonic pulse velocity test. The round shapes of three reinforced concrete (RC) columns were tested: a non-retrofitted RC column as a control, a carbon fiber-reinforced polymer (CFRP) column, and an Fe-SMA retrofitted column. During the cyclic loading test, the degradation of the column was defined based on the decrease in compressional wave velocities. The experimental results demonstrated a maximum improvement of 175% in seismic performance of the Fe-SMA retrofitted RC column compared with the controlled column. This is primarily owing to the active constraints of the SMA, which were quantified based on ultrasonic velocities. Furthermore, the surface degradation process was identified using external cracks, which were not visible in the CFRP retrofitted RC column.
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