cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.12755/isec.res.2014.48
title: PRACTICAL SEISMIC STRENGTHENING OF R/C BEAM-COLUMN JOINTS WITHOUT LATERAL REINFORCEMENTS IN DEVELOPING COUNTRIES

description: Several destructive earthquakes in developing countries in recent years have revealed that a large number of reinforced concrete (R/C) buildings contained no lateral reinforcements in beam-column joints. Severe damage was caused to such beam-column joints due to poor structural capacities, and resulted in complete/story collapse of buildings and loss of human lives. Considering the economic and technical conditions in developing countries, this paper proposes a practical seismic strengthening method for applying R/C wing walls to this kind of substandard beam-column joint. A feasible design concept is presented exemplifying an exterior beam-column joint, representing a typical earthquake-damaged joint by the 2009 West Sumatra, Indonesia earthquake. In this study, two 3/4-scale exterior beam-column joint specimens were constructed with the common structural details, and one of them was strengthened by R/C wing walls. Their seismic performance was evaluated through static cyclic loading tests. It was found that the strengthened specimen behaved a ductile manner with beam yielding, whereas the unstrengthened control specimen prematurely failed at the joint. The proposed strengthening method significantly increased the moment resistance of the joint. Fundamental experimental data could be successfully obtained to propose the calculation procedure for designing R/C wing walls for practical strengthening.
DOI: 10.12755/isec.res.2014.49
title: SHEAR REPAIRED RC BEAM BY FRP BONDING WITH EXTERNAL POST-TENSIONING

description: Various factors, including increase in traffic volume and weight, structural aging, and environmental impact, cause damage in structural members. This raises the importance of the maintenance, rehabilitation, and strengthening of reinforced concrete members. External post-tensioning is one of the widely-used strengthening techniques in many countries due to its advantages over other strengthening methods. Although flexural strengthening of existing structural members is a well-established method, shear strengthening of structural members, especially with existing shear cracks, has attained very little attention from researchers. Similarly, external fiber-reinforced polymer (FRP) bonding for shear strengthening of structural members, especially with existing shear cracks, is a relatively new area of research. This paper presents the results of an experimental study on the shear strengthening of reinforced concrete (RC) beams with existing shear cracks by external post-tensioning and external FRP bonding. The test result showed that the combined strengthening technique of external post-tensioning and external FRP bonding can effectively increase the shear capacity of RC beams with existing shear cracks.
DOI: 10.12755/isec.res.2014.50
title: FLEXURAL PERFORMANCE OF RC BEAMS WITH NEAR SURFACE MOUNTED CFRP PLATE

description: This study investigates the flexural performance of RC beams strengthened with Near Surface Mounted CFRP plate. In construction, deterioration tends to occur due to changes in loading capacity, improper design, or poor quality of workmanship. This will result in long-term effects as the strength decreases over time. To prepare for the long-term effects, the Near Surface Mounted (NSM) method can be used to strengthen the RC members. This is to ensure that a structure can continuously function for its intended purpose. Three beams of 125 mm x 300 mm x 1800 mm (width; height; length) were constructed for this study. The first beam was not strengthened, the second beam was strengthened with a CFRP plate horizontally positioned on the tension zone, and the third beam was strengthened with a CFRP plate vertically positioned on the tension zone. All three beams were then tested under a four point bending test. Results show that the beam with horizontal strengthening was able to increase the flexural strength of about 22% compared to the control beam, while the beam with vertical strengthening was able to increase the flexural capacity of about 43% compared to the control beam. This indicates that the NSM method can be used to significantly increase the flexural strength of RC members.
DOI: 10.12755/isec.res.2014.51
title: MODELING OF CONCRETE BEHAVIOR UNDER BIAXIAL FATIGUE LOADING WITH VARIOUS MEAN STRESSES

description: In this paper, a general approach is proposed for modeling the behavior of concrete under biaxial fatigue loading with various mean stresses (stress range). Using damage mechanics and principles of thermodynamics, a generalized bounding surface approach is proposed. It is mentioned that limit surface, determined by model, is a condition in which the number of fatigue loading is set to one. In other words, limit surface represents the strength of material under monotonic loading with various load paths. By increasing the number of loading cycles, the limit surface is allowed to contract and to form surfaces representing residual strength curves. The evolution of the subsequent surfaces depends on load magnitude, load range (mean stress), and load path. Within the formulation, a softening function is postulated which captures the reduction in the strength of concrete under fatigue loading. A comparison of model predictions against experimental data shows a good correlation.
DOI: 10.12755/isec.res.2014.52
title: EVALUATION OF S-WAVE AMPLIFICATION SPECTRUM USING MICROTREMORS

description: To evaluate the site effects above the engineering base rock with an S-wave velocity of 300m/s, microtremor measurements on the ground surface were conducted in Maizuru, Japan. An estimation method of S-wave amplification spectrum using the microtremor H/V spectral ratio was applied at the ground surface, estimating S-wave amplification spectrum without any ground information based on the microtremor measurement results. It was found that the evaluation of S-wave amplification spectrum needs a revision on the microtremor H/V spectral ratio, using some coefficients on the microtopography classification and the shape of the microtremor H/V spectral ratio.
DOI: 10.12755/isec.res.2014.53
title: NUMERICAL DYNAMIC ANALYSIS OF ORTHOTROPIC PLATES UNDER LOCALIZED BLAST LOADING

description: This paper analyzes the dynamic response of fixed supported orthotropic plates under localized blast loading using the method of modal superposition. The analysis procedure is used to quantify the linear transient response of such plates to the localized blast load at different positions. Many studies are currently available, in which the blast load is considered to be spatially uniform across the plate, with a temporal distribution described by a Dirac delta function. The novel aspect considered here is the case for which the blast load is modeled as a linear triangular function, and the orthotropic plate is fixed along its edges. A Mathematica program is used to solve the first and the second auxiliary Levy-type problem to determine the values of the natural frequencies of the system. The results presented here are collected from the results of analyses performed on localized blast-loaded orthotropic plates, for a variety of parameters important with regard to the dynamic response. Conclusions are drawn concerning the influence of the various parameters on the nature of the orthotropic-plate response.
DOI: 10.12755/isec.res.2014.54
title: SEISMIC EVALUATION OF CODE DESIGNED STEEL PLATE SHEAR WALLS UNDER MAINSHOCK-AFTERSHOCK EARTHQUAKE SEQUENCES

description: Structures are often subjected to sequences of mainshock and aftershocks during their service life. Strong aftershocks have been known to cause extensive structural damage and losses of human lives in addition to the damage and losses of the mainshock. Steel plate shear walls (SPSWs) have recently attracted considerable interest as a promising lateral-resisting system in seismic-prone regions. The SPSWs consist of steel beams and columns with a thin infill steel plate. The unstiffened thin plates are expected to buckle at low seismic loads and develop tension field action that enables favorable ductility and energy dissipation. The American Institute of Steel Construction's Seismic Provisions prescribe a capacity-based design methodology that uses SPSWs as primary seismic force resisting systems, and require the design of SPSWs to be consistent with the design requirements for other ductile steel seismic force resisting systems. This paper presents numerical analysis of a code-designed eight-story SPSW building that was subjected to consecutive mainshock-aftershock earthquake events. Ground motions developed for the SAC project were selected and scaled to simulate the main shock events at maximum considered earthquake (MCE) level, and large aftershocks events at design base earthquake (DBE) level. Nonlinear response history analysis using the finite element program OpenSees were conducted to investigate the performance of the code designed SPSWs. It was demonstrated that the designed SPSW has good performance under mainshock-aftershock sequences.
DOI: 10.12755/isec.res.2014.55
title: MODAL PARAMETER ESTIMATION OF LTI SYSTEM USING HILBERT-HUANG TRANSFORMATION OF MEASURED WIRELESS SENSOR DATA

description: An iterative Hilbert-Huang transformation (HHT) based algorithm is developed to extract the modal parameters of a linear time invariant (LTI) system excited by recorded non-stationary ground motion. The acceleration responses are measured using wireless sensors, which are filtered to avoid mode mixing prior to evaluate the instantaneous amplitude and phase using HHT. The band width is adjusted in successive iterations to achieve convergence in modal parameter estimation. The numerical study presented in this work discusses the efficiency of the identification strategy in the light of noise contaminated earthquake responses.
DOI: 10.12755/isec.res.2014.56
title: A MODEL SHAKING TABLE TEST INVESTIGATION ON AN ASSEMBLY FRAME

description: A shaking table test on a two-story aluminum alloy space frame model with mortise and tenon joints were carried out. The natural frequency and the damping ratio of the model in two directions were obtained by vibration frequency sweep. Inputting EL-Centro (N-S) 0.1g, 0.2g and 0.4g seismic motion, the strain, displacement and acceleration response of the model structure were investigated. It shows that the mortise and tenon joint frame has lower natural vibration frequency, higher damping ratio, better ductility, and better seismic performance than the corresponding rigid connecting structure.
DOI: 10.12755/isec.res.2014.57
title: SEISMIC RESPONSE OF A FLAG-SHAPED HYSTERETIC BEHAVIOR UNDER GROUND MOTIONS

description: Self-centering systems have attracted significant interest in earthquake-engineering research, due to their excellent performance under simulated seismic loading through their self-centering capabilities. A comprehensive parametric study is presented to compare the ductility demands on single-degree-of-freedom (SDOF) systems, when subjected to ground motions with a probability of exceedance of 10% in 50 years in California. The influences of different parameters were analyzed under SDOF structural responses in terms of displacement ductility and absolute acceleration. The responses of the flag-shaped hysteretic SDOF systems were also compared against the responses of similar bilinear elasto-plastic hysteretic SDOF systems. Two ensembles of far-field and near-fault historical earthquake records, corresponding to ordinary earthquakes, were used for the parametric study to compare the ductility demands. Although a flag-shaped hysteretic SDOF system of equal or lesser strength can often match or better the response of an elasto-plastic hysteretic SDOF system with almost no residual drift, the analysis shows that seismic design of self-centering systems should account for the difference between far-field and near-fault ground motion.
DOI: 10.12755/isec.res.2014.58
title: UTILIZATION OF ARMA MODELS TO MEASURE DAMAGE POTENTIAL IN SEISMIC RECORDS

description: ARMA parameters are developed to assess the damage potential in seismic records. The parameters are chosen to fit acceleration time series of particular earthquake records using the maximum-likelihood method. For each event, a set of random accelerograms is generated and used to establish statistically-valid structural response spectra. Since the number of earthquake accelerograms in any seismic region is limited, non-stationary stochastic models are used to characterize earthquake ground motion. From a sample of earthquakes, the mean and variance of response spectral ordinates are obtained for damage predictors. Structural design spectra for earthquakes are based on smoothed linear response spectra obtained from different events scaled by their peak values. Such an approach does not incorporate other characteristics of the excitation represented by measured data. Samples of acceleration records are generated for each event. In this study, individual records for an earthquake are treated as one realization of an underlying non-stationary process that actually characterizes the earthquake. This research provides a reliable description of the information contained within acceleration records, and can also provide a reasonable estimate of the average nonlinear demand spectra.
DOI: 10.12755/isec.res.2014.59
title: A STUDY OF GROUTING MATERIAL BLEEDING PROPERTIES FOR PRESTRESSED CONCRETE

description: This study investigates the workability, bleeding, and volumetric change of grout widely used in Korea for securing the quality of grout applied in prestressed concrete (PC) bridges. The results reveal that the workability satisfies all the criteria for the grout specified in Korea. It appears that bleeding increases by 5.7 to 6.7 times when the tendon is arranged, regardless of the quality of grout, and that the height and inclination of the grout sample significantly affect bleeding. Furthermore, the arrangements of tendons were seen to prevent expansion even in grout using expansive aluminum powder, but was also seen to let shrinkage occur with a significant increase in bleeding. The conclusion is that it is necessary to establish a new testing method and apply high-performance grout for securing the quality of the grout used in PC bridges.
DOI: 10.12755/isec.res.2014.60
title: IMPACTS OF PRE-STRESS LOSS ON THELONG-TERM DEFLECTION FOR LONG-SPAN PC CONTINUOUS GIRDER BRIDGE

description: In order to analyze the impacts of pre-stress loss on the long-term deflection for long-span PC continuous girder bridges, this paper presents a numerical analysis using the finite element analysis software MIDAS/Civil based on a long-span PC continuous box-section girder bridge in Shijiazhuang. Once the 3-D finite element model was established, the influences of different pre-stress loss levels and locations were analyzed in a numerical simulation. Pre-stress loss is often the key reason for long-term deflection in long-span PC continuous girder bridges, so we can estimate the development of deflection by considering these factors during the operation.
DOI: 10.12755/isec.res.2014.61
title: STATE OF THE ART IN REPAIR AND STRENGTHENING METHODS OF DETERIORATED CONCRETE BRIDGE STRUCTURES

description: This paper summarizes the current development for repairing and strengthening deteriorated concrete bridge structures in Japan, especially those deteriorated due to alkali-silica reaction (ASR) and chloride attack. Generally, surface treatments are applied as the repair method due to ASR and chloride attack. Barrier coating and penetrating sealer are two methods that are actively applied as surface treatments in Japan. An investigation of repaired concrete bridge structures using these methods indicate that acrylic-based surface coatings are the most suitable method for repairing concrete structures, and the silicon-based compounds repair concrete structures with low risk of corrosion. Furthermore, the use of sodium or potassium for silicate-based surface treatments should be avoided, as these solutions may exacerbate ASR. This finding was backed up by an accelerated mortar bar test experiment under a modified ASTM C1260 test method. The results show that large ASR expansion occurred on mortar bars immersed in sodium silicate solution (Na2SiO3). In regards to strengthening, CFRP sheet bonding, concrete jacketing and PC-confined method with prestressing steel wire were applied for concrete bridge structures. Especially for the PC-confined method, this method can be applied not only as an earthquake strengthener but also an ASR expansion controller on deteriorated bridge piers.
DOI: 10.12755/isec.res.2014.62
title: AN EXAMINATION OF HYBRID STRUCTURES RENOVATED FROM OLD RAILWAY STEEL BRIDGES

description: This research offers a new composite-revamping method for railway bridges. It assumes that the composite remodeling process of existing steel bridges has no specific fissure damages or serious corrosion, and effectively makes use of relatively new materials. The effects of noise reduction and improved stiffness were further confirmed through hammer-impact tests (vibration and noise measurement tests) in order to prove the efficacy of the composite remodeling.
DOI: 10.12755/isec.res.2014.63
title: A PRECAST REINFORCED CONCRETE SYSTEM WITH CONTROLLED DYNAMIC PROPERTIES

description: The precast reinforced concrete system with controlled dynamic characteristics allows, together with demountability, an efficient optimization of a load-bearing system?s response to external dynamic and static loading effects and impacts. The essential elements of the system are the joints of load-bearing reinforced concrete precast units with high ductility allowing the absorption of dynamic energy and the optimization of the load-bearing system?s response to technical as well as natural seismicity. Another significant feature of such joints is their ability to eliminate outside noise (e.g., traffic, building activity, industrial activity) below the threshold of hearing; this improves the quality of the interior environment and allows land development in areas with increased noise levels, traffic, etc. The system may also be analogically applied in areas with poorer foundation conditions, in areas with underground traffic, in undermined areas, and in areas with high seismic risks.
DOI: 10.12755/isec.res.2014.64
title: INFLUENCE OF FLANGE WIDTH ON THE SHEAR-LAG EFFECT FOR PC SKEBOX-SECTION GIRDER BRIDGES

description: Skewed box-section girder bridges are widely used in the proceeding of the road network construction. Ignoring the shear-lag effect will give rise to the instability and failure of bridges. The single-factor calculation theory of orthogonal box-section girder bridges cannot be applied to the calculation of the shear-lag effect of skewed box-section girder bridges. In this paper, simply-supported skew box-section girder bridge models with different widths of flanges were built by using the finite element software ANSYS. The distribution laws of shear-lag effect in the transverse and vertical of skewed box-section girder bridges were more obvious with an increase in the flange width.
DOI: 10.12755/isec.res.2014.65
title: EXPERIMENTAL EVALUATION OF FLEXURALCAPACITY OF FULL SCALE PRECASTCONCRETE SHEETPILE

description: A flexural capacity test is presented of a long precast concrete sheetpile system, intended as a protection wall for a water storage canal bank in soft-ground conditions, for a nursing college in Penang, Malaysia. The precast concrete sheetpile with a length of 7 m and a maximum exposed corrugated-section height of 1.8 m, was designed at Ultimate Limit State (ULS) bending moment of 175 kNm. A total of 2 specimens of precast concrete sheetpiles were tested in the Heavy Structure Laboratory at School of Civil Engineering, Universiti Sains Malaysia. The test method specified in Malaysian Standard MS 1314 was adopted. The results showed that the capacity of Specimens 1 and 2 were respectively 1.49 and 1.48 times higher than the designed capacity at ULS. The test set-up, to reflect the practical behavior of precast concrete sheetpile, and the test procedures are also described.
DOI: 10.12755/isec.res.2014.66
title: USE OF FERROCEMENT PANEL AS REINFORCEDCONCRETE SLABS WITH LIGHTWEIGHTBLOCKS INFILL

description: This paper is part of an experimental series to investigate the potential use of ferrocement panels as a permanent form of reinforced concrete slabs with lightweight blocks infill. The ferrocement panels used are engineered with polyvinyl alcohol (PVA) fiber to have a strain hardening which can be characterized as high-performance fiber-reinforced cementitious composite (HPFRCC), called Engineered Ferrocement (EF). In the experimental work, ferrocement control panels and hybrid ferrocement panels were tested for strength capacity and hard strain behavior through flexure, toughness, and multitrack forming. The results showed that by using the ideal fiber/wire mesh content, the hybrid ferrocement panels act as a strain-hardening cementitious material, and successfully increasing the flexure strength compared to the control-group ferrocement. The initial investigation indicates that hybrid PVA fiber ferrocement in tensile zones can be successfully used as permanent form.
DOI: 10.12755/isec.res.2014.67
title: OFFSHORE PLATFORM DECOMMISSIONING: THE NEED FOR A COST INDEX

description: Globally, decommissioning of offshore installations has been considered to be one of the biggest challenges facing the oil and gas industry. International conventions on ocean safety now emphasize complete removal rather than reefing. This option is complex, requiring scarce technical expertise and environmental sensitivity in challenging environments. Both governments and operators must develop accurate cost estimates for offshore platform decommissioning. The government requires them to guide its negotiations with decommissioning contractors, while operators require them to determine annual remittances to decommissioning accounts built into modern day oil and gas concession contracts. Consequently, a reliable cost estimation method could be used to define a Zone of Possible Agreement (ZOPA) for offshore platform decommissioning in Malaysian waters before engaging in negotiations with contractors. This would improve value for money and also ensure time value for money. This article looks at current challenges concerning a proposed offshore platform decommissioning price index for Malaysian waters. The conclusion is that these indices are helpful tools for comparisons between conditions across several variables, and are easy to update once developed.
DOI: 10.12755/isec.res.2014.68
title: PERCEPTIONS OF THE RETENTION SYSTEM IN THE CONSTRUCTION INDUSTRY

description: The retention system of withholding a portion of payment to contractors and subcontractors is a peculiar feature of the building industry. In the past decade or so there has been much discussion about the practice of retentions in the US and UK construction industries. Anecdotal evidence without concerted research suggests that problems exist within the practice in the New Zealand construction industry, which this study will address. Retention practice affects the whole construction supply chain, but the effect the practice has on each party varies significantly. Thirteen interviews were carried out with experienced construction industry professionals, including clients, contractors, subcontractors and consultants. An analysis of their recorded views and perceptions revealed diverse views. Most agreed that problems with retention are very serious, the worst affected being the subcontractors who do not have much control or say. However, they said, in the absence of any better alternative, the practice is working well in its current form. Further research will work out some alternatives to the traditional retention practice so as to create more balance and fairness for all the parties involved in the supply chain.