Evaluasi Kinerja Struktur Gedung Bertingkat Menggunakan Pendekatan Desain Berbasis Kinerja

In Indonesia, earthquake-resistant structures are governed by SNI as design codes, which are updated on a regular basis. As a result, existing buildings with outdated requirements must be reviewed so that the building's performance may be assessed in light of the most recent codes. Pushover analysis and direct displacement-based design are used to characterize the real condition of the building in order to assess its performance. The 7-story reinforced concrete building structure in this study was designed according to SNI 03-2847-2002 and SNI-1726-2002. This structure will be evaluated utilizing the FEMA 440 and FEMA 356 procedures, as well as SNI 1726:2019. The results show that the structure meets the minimal performance limit criteria (which is life safety) in terms of displacement and drift values from the pushover analysis, based on FEMA 356 and FEMA 440 performance levels. The evaluation indicates better structural response parameter values (R, Ω0, and Cd) than that of SNI 1726:2019, indicating that the building performance is good and capable of withstanding the design earthquake load.

Alternative approach in Partial Capacity Design (PCD) by using predicted post-elastic story shear distribution

The Capacity Design Method is an approach widely used to design earthquake resistant structures. It allows the structures to dissipate earthquake energy by forming plastic hinges through beam side sway mechanism. In the design process, the columns need to be designed stronger than the beams connected to them. Several previous studies have been conducted to propose alternative method allowing partial side sway mechanism namely the Partial Capacity Design (PCD) Method. In this method, selected columns are designed to remain elastic and the plastic hinges are allowed to occur only at the columns base. These columns are designed to resist increased forces. Despite of some successful attempts, PCD method still needs to be developed because sometimes the intended mechanism was not observed. This study proposes a new approach to improve the Partial Capacity Design (PCD) method. Symmetrical 6 and 10 story buildings with 7 bays are analyzed using seismic load for city of Surabaya. Structure behavior under non-linear static analysis is well predicted by this approach. However, under non-linear dynamic analysis, a few unexpected plastic hinges of elastic columns were observed at upper stories. But it should be noted that the earthquake used for performance analysis (maximum considered earthquake) is 50% larger than the one used for design (earthquake level corresponding to elastic design response spectrum).

DYNAMIC RESPONSE AND STABILITY ANALYSES OF AKOSOMBO DAM USING NUMERICAL ANALYSIS

Dams are very important in Ghanas economic development and environmental improvement. Although Ghana dams are seismically far from the active zone, accurately analysed dams should be evaluated since failure could severely impact the people in the flood environment and the regions economy on a large scale. This paper proposes a numerical procedure for the static, slope stability, and dynamic analysis of the Akosombo embankment dam. Nineteen horizontal acceleration time histories recorded data was used based on Maximum Design Earthquake (MDE), Maximum Credible Earthquake (MCE), Design Basis Earthquake (DBE) and Operating Basis Earthquake (OBE) data. The numerical results estimated showed that the Akosombo embankment dam is likely to experience moderate deformations during the different design earthquakes. The result also indicated that non-linear analysis capable of capturing dominant non-linear mechanisms could be used to assess the stability of embankment dams. The factor of safety (FS) calculated was greater than 1.5 for high reservoir, rapid drawdown condition and low reservoir condition whereas, the FS values were found to be 1.42 for slow drawdown condition.

Evaluation of the performance of high-rise building structures with plan ‘H’ shaped for earthquake with height increase (Case study: Apartment Urban Sky-Bekasi)

Currently, Bekasi City is developing into a residence for an urban, industrial center, and built apartments. One of them is the Urban Sky-Bekasi Apartment. This researched raises by an apartment as a case study to evaluate the performance of multi-story building structures as earthquake-resistant buildings. This researched conduct by add the original building height to 8 m (a basic height equals 102 m and a new height equals 110 m) to analyze whether the planning data made could still bear the same load with different heights and could still be categorized as earthquake-resistant buildings. From the results of the SAP-2000 output. The value of the basic static and dynamic shear forces in a 110 m building is always greater than a 102 m building in both the X and Y directions, this indicates that the taller a building is, the higher the design earthquake force used will be. The displacement in a 110 m building is always bigger than a 102 m building in both the X and Y directions. The weakest strength of the structure in a 110 m building is on the 29th floor in the X directions and Y directions, while the 102 m building is on the 26th floor in the X directions and 24 directions. It shows that with the addition of high SAP-2000 output data such as displacement, drift ratio, and other data after analysis shows that a 110 m building is categorized as an earthquake-resistant building according to SNI 1726-2012.

Identifying geometric configuration of earthquake-resistant buildings

Indonesia is an earthquake-prone area because it is located at the world's most active tectonic plates and hundreds of local faults. Obviously, there have been many earthquake victims caused by collapsed buildings, hence the need for earthquake-resistant construction. However, there is not much guidance for architects to design earthquake-resistant buildings. This research proposes guidance for architects on how to design building forms relatively able to resist earthquakes. The simulation experiment method involving 32 building models in various forms was employed. The experimental results were then analyzed with modal analysis in ETABS and SVA for architectural design. Based on the analysis report, some guidelines were proposed: 1). Avoid buildings that are too slender, use the slenderness ratio H/D ≤ 2, 2). Avoid soft stories where the ratio of the top column height (h) to the bottom column height (h1) ≤ 0.8, 3). Use symmetrical shapes with 1 or 2 axes and avoid shapes with random compositions, 4). Use the additive and subtractive mass transformation ≤ 15%, 5).Strengthen the structural elements, install shear walls, or use dilatation to minimize potential torsional irregularities and non-parallel system irregularities of L, T, U, +, and Z forms6). Avoid using non-axial asymmetrical forms.

Performance Based Seismic Design of Reinforced Concrete Building by Non-Linear Static Analysis

In past two decades earthquake disasters in the world have shown that significant damage occurred even when the buildings were designed as per the conventional earthquake-resistant design philosophy (force-based approach) exposing the inability of the codes to ensure minimum performance of the structures under design earthquake. The performance based seismic design (PBSD), evaluates how the buildings are likely to perform under a design earthquake. As compared to force-based approach, PBSD provides a methodology for assessing the seismic performance of a building, ensuring life safety and minimum economic losses. The non-linear static procedures also known as time history analysis are used to analyze the performance of structure . Plastic hinge formation patterns, plastic rotation, drift ratio and other parameters are selected as performance criterias to define different performance level. In this paper, a five-storey RC building is modelled and designed as per IS 456:2000 and analyzed for lmmediate occupancy performance level in ETABS2015 softwere. Analysis is carried out as per FEMA P58 PART 1 & 2. Plastic hinges as per FEMA273. From the analysis, it is checked that the performance level of the building is as per the assumption

Cyclic engagement of hysteretic steel dampers in braced buildings: a parametric investigation

Hysteretic steel dampers have been effectively used to improve the seismic performance of framed buildings by confining the dissipation of seismic energy into sacrifical, replaceable devices which are not part of the gravity framing system. The number of cycles sustained by the dampers during the earthquake is a primary design parameter, since it can be associated to low-cycle fatigue, with ensuing degradation of the mechanical properties and potential failure of the system. Current standards, like e.g. the European code EN 15129, indeed prescribe, for the initial qualification and the production control of hysteretic steel dampers, cyclic tests in which the devices are assessed over ten cycles with amplitude equal to the seismic design displacement dbd. This paper presents a parametric study focused on the number of effective cycles of the damper during a design earthquake in order to assess the reliability of the testing procedure proposed by the standards. The study considers typical applications of hysteretic steel dampers in low and medium-rise steel and reinforced concrete framed buildings and different ductility requirements. The results point out that the cyclic engagement of the damper is primarily affected by the fundamental period of the braced building and the design spectrum, and that, depending on these parameters, the actual number of cycles can be substantially smaller or larger that recommended by the standards. A more refined criterion for establishing the number of cycles to be implemented in testing protocols is eventually formulated.

First Use of Fragile Geologic Features to Set the Design Motions for a Major Existing Engineered Structure

ABSTRACT We document the first use of fragile geologic features (FGFs) to set formal design earthquake motions for a major existing engineered structure. The safety evaluation earthquake (SEE) spectrum for the Clyde Dam, New Zealand (the mean 10,000 yr, ka, return period response spectrum) is developed in accordance with official guidelines and utilizes constraints provided by seven precariously balanced rocks (PBRs) located 2 km from the dam site and the local active Dunstan fault. The PBRs are located in the hanging wall of the fault. Deterministic PBR fragilities are estimated from field measurements of rock geometries and are the dynamic peak ground accelerations (PGAs) required for toppling. PBR fragility ages are modeled from B10e cosmogenic isotope exposure dating techniques and are in the range of 24–66 ka. The fragility ages are consistent with the PBRs having survived at least two large Dunstan fault earthquakes. We develop a PGA-based fragility distribution from all of the PBRs, which represents the cumulative toppling probability of a theoretical random PBR as a function of PGA. The fragility distribution is then used to eliminate logic-tree branches that produce PGA hazard curves that would topple the random PBR with a greater than 95% probability (i.e., less than 5% survival probability) over a time period of 24 ka (youngest PBR fragility age). The mean 10 ka spectrum of the remaining hazard estimates is then recommended as the SEE spectrum for the dam site. This SEE spectrum has a PGA of 0.55g, which is significantly reduced from the 0.96g obtained for a preliminary version of the SEE spectrum. The reduction is due to the combined effects of the PBR constraints and a substantial update of the probabilistic seismic hazard model. The study serves as an important proof-of-concept for future applications of FGFs in engineering design.

Seismic Design and Performance Assessment of Frame Buildings Reinforced by Dual-Phase Steel

To improve the durability and serviceability of reinforced concrete structures, different variants of dual-phase reinforcing steel were developed within the research project NEWREBAR. The investigated variant of the new material, termed DPD2 steel, has a specific microstructure that increases the corrosion resistance, but its yielding strength is less than that of Tempcore steel B500B. DPD2 steel has no yielding plateau, which is characteristic of conventional reinforcing steel. Thus, it was investigated whether the current building codes can be used to design earthquake-resistant concrete structures reinforced by DPD2 steel bars. For this reason, three multi-story reinforced concrete frame buildings were designed according to Eurocode by considering DPD2 steel and, for comparison reasons, Tempcore steel B500B. Based on the nonlinear model, which was validated by cyclic test of columns, the seismic performance of DPD2 buildings was found to be improved compared to those designed with conventional B500B reinforcing steel. This can mainly be attributed to the substantial strain hardening of the DPD2 steel, which increases the overstrength factor of the structure by about 10%. However, for the improved seismic performance, the amount of steel in DPD2 buildings had to be increased in the design by approximately 20–25% due to the smaller yield strength of DPD2 steel. Nevertheless, it was demonstrated that Eurocode 8 could be used to design earthquake-resistant frame building reinforced with dual-phase reinforcing steel DPD2.