Load Resistance Factor Design Research Articles

Explicit consideration of geomaterial uncertainties in the load resistance factor design of piles driven into rock-based intermediate geomaterials

The study presents a method for estimating the end bearing of piles driven into rock-based intermediate geomaterials (IGMs). Existing design methods, rooted in soil mechanics, often fall short when applied to IGMs. Moreover, the geomaterial (geological and ground properties) uncertainties are neglected and the piles are designed based on subsurface information from distant boreholes. To address this gap, the study introduces an approach that explicitly considers geomaterial uncertainties by combining empirical models and geostatistical simulation to predict end bearing. Using data from 87 piles driven into various rock-based IGMs with dynamic load testing as the construction control technique, this study introduces the Proposed Design Method (PDM) for the prediction of end bearing. PDM is compared to the Current Design Method (CDM), which is based on traditional soil-mechanics methods. Predictions from these methods are subsequently evaluated against the measured end bearings. The results demonstrate that while the PDM yields comparable predictions to the CDM, it offers a more robust consideration of geomaterial uncertainties. The PDM leads to an approximate 13.60% to 19.35% increase in uncertainties compared to CDM across various IGMs. These findings advance the understanding of pile behavior in the presence of geomaterial uncertainties and inherent variability.

Evaluation of External and Internal Stability for retaining wall with sloping backfill by load resistance factor design (LRFD) method by using an excel spread sheet

Evaluation of External and Internal Stability for retaining wall with sloping backfill by load resistance factor design (LRFD) method by using an excel spread sheet

Experimental study of novel wrapped CFRP-strengthened CFS-to-sheathing screw connections

Cracking damage of the sheathing wallboards in screw connections is the typical failure mode of cold formed steel (CFS) structures under seismic effects, which limits the shear capacity and weakens the hysteretic performance of CFS structures. To improve the shear performance of CFS-sheathing screw connections, a novel screw connection with carbon fiber reinforced polymer (CFRP) reinforcement is proposed in this paper. Cyclic tests were conducted on a total of 26 sets of screw connections with different configurations and wall sheathings, and the effects on the failure modes and shear performance of the connections with and without CFRP reinforcement were investigated. The strengthening effects of the sheathing material, panel thickness and end distance on the shear properties of the connections were discussed. The results indicated that (1) except for specimens with 15 mm end distance, CFRP reinforcement can effectively avoid brittle cracking failure of the connections, and the failure mode tended to ductile failure of the bearing and pull-through damage. (2) in addition to the stiffness, the shear strength, deformation capacity, ductility and energy dissipation capacity of CFRP-strengthened connections are significantly enhanced. The effect of CFRP on the shear performance improvement of connections sheathed with gypsum board (GWB) and magnesium glass board (MgO) is greater than that of oriented strand board (OSB), and the strengthening effect is not significantly influenced by the board thickness. A toughness evaluation method for CFRP-strengthened connections was proposed, and the design formulae for the shear strength of the CFRP-strengthened screw connections were recommended based on the load resistance factor design (LRFD) method and allowable strength design (ASD) method.

Ultimate Shear Strength of Pitted Plates with Crack Using Finite Element Method

_ Ultimate strength of thin steel plates was studied under shear loading when pitting corrosion and cracking occur simultaneously. Nonlinear finite element method was used and the effects of different geometrical parameters, such as crack position, crack length, pit depth, pit diameter, number of the pits, and the inclination angle of the crack, were investigated. It was found that the degree of the pitting (DOP) significantly reduces the ultimate shear strength of the pitted plates when the corrosion is low. For high amount of corrosion, the reduction of the ultimate shear strength remains the same regardless of the amount of the DOP. In plates with short cracks, the crack length has no influence on the reduction of the ultimate shear strength. Also, it was found that the position of the crack is more effective than the length of the crack on the reduction of the ultimate shear strength of the cracked plates. In the cracked-pitted plates, there was no interaction between crack and pit for extremes value of DOP. For low value of DOP, the ultimate shear strength of the cracked-pitted plate was the same as the cracked plate, and for large value of DOP, it is the same as pitted plate. Introduction According to a study performed between 2002 and 2008 by American Bureau of Shipping (ABS) (“Review of Current Practices of Fracture” 2012), majority of reported fractures of the ships were structural failures, such as weld defect, buckling, fracture, and cracking. Cracks and corrosion are two more common defects, which are the main reasons of the failure of the aged steel structures. Plates and stiffened plates are the main structural elements in many structures, including airplanes, bridges, offshore structures, and ships. Ultimate strength evaluation of these structural elements is crucial for rational design of structures, such as Load Resistance Factor Design (LRFD) methods in civil engineering and Ultimate Strength (UTS) evaluation in ship structure. Many studies are carried out to evaluate ultimate strength of intact and damaged plates/ stiffened plates under in-plane compressive stress. Ranji (2012) studied ultimate strength of plate with general corrosion under in-plane compression. He proposed a spectrum for random generation of corroded surface and ultimate strength of corroded plate was evaluated using computer code ANSYS. Ranji and Zarookian (2015) analyzed ultimate strength of cracked stiffened plates with cracks having different stiffeners numerically.

LRFD Approach for Load Rating U.S. Army-Owned Bridges That Require Engineering Judgment

As part of their 2020 Biennial Inspection Program, the U.S. Army is conducting a load rating effort for its bridges located at military installations throughout the United States. To date, 201 structures at 26 army bases are being evaluated for both civilian and military vehicles. Seventy-two of these structures are reinforced concrete bridges with unknown reinforcement which must therefore be rated using engineering judgment. The American Association of State Highway and Transportation Officials’ (AASHTO) Manual for Bridge Evaluation provides guidance for these structures when the live loads are civilian vehicles. For army-owned bridges, however, an allowable military load classification must also be determined. A procedure called “correlation classification” is currently used to determine the proper military load classification for a particular bridge. The current procedure, however, is based on the allowable stress method. To allow the use of load resistance factor design (LRFD), a new correlation equation and methodology using LRFD principles was developed. The methodology, however, requires the load rater to incorporate knowledge about the bridge into the load rating process. For older bridges with lighter design vehicles, and low the average daily traffic bridges, the correlation concept was also used to determine if a posting was required for state legal and emergency vehicles. This exercise demonstrated that the current correlation equation can be successfully modified to incorporate LRFD principles and applied to determine the military load classification for reinforced concrete structures that require engineering judgment. The application of the new correlation equation is illustrated with two examples: a reinforced concrete beam bridge and a box culvert.

A stochastic framework for the assessment of horizontally curved aluminium bridge decks on steel girders

A purpose-developed structural reliability assessment (SRA) framework for the evaluation of horizontally curved aluminium alloy bridge decks on steel I-girders of centre subtended angle, θ≤34.4 with precinct on the American association of state highway and transportation officials (AASHTO) load resistance factor design (LRFD) specification is presented. The finite element analysis (FEA) simulations were performed in the ABAQUS© CAE, whilst the probabilistic assessment model was developed using the first-order reliability method (FORM). Besides performing detailed design checks and a validation exercise, the developed SRA framework was used to examine the structural behaviour of the bridge assembly in the presence of stochastic design truck axle loads, structure’s self-weight, among other loads, whilst varying geometric properties. The most critical structural responses chosen at salient points obtained via FEA simulation is applied in deriving the limit state function (LSF), which is then substituted into the stochastic model within the purpose-developed iterative FORM algorithm to calculate the reliability index (RI), β of the structure. It is shown that the proprietary AlumadeckTM system conforms with the LRFD specification, which stipulates that the target value of RI is 3.5 for resistance factor (RF) of 1.0 (assuming 80% composite action compression flange). The result also reveals that the RI shows a strong dependence on the composite action between the deck and the girder for RF of 1.0 full composite action (considering the failure of the bottom flange), indicating the safety index is within acceptable limits. Furthermore, it is revealed that the minimum composite action for safety is 40%, corresponding to a safety index of 1.16. Hence, it can be inferred from the foregoing that the AlumadeckTM can withstand the stochastic axle load it is subjected to considering the HL-93 load design condition and satisfies all design criteria considered from a stochastic perspective based on the AASHTO LRFD guidelines, provided the minimum stiffner thickness tstiffner of 7mm is adopted (based on the FEA simulation results). A case study conducted herein established that the structural configuration selected (i.e. depth at 2.4m, flange thicknesses at 21mm, flange width at 50cm and web thickness at 16mm) demonstrates the structural safety and durability of the bridge system coupled using the AlumadeckTM.

ALTERNATIF DESAIN STRUKTUR ATAS JEMBATAN RANGKA BAJA TIPE HALF THROUGH ARCH PADA JEMBATAN TRISULA BLITAR, JAWA TIMUR

The bridge is an important infrastructure in the transportation system, namely as a means of crossing the river, as well as connecting between cliffs. The bridge has various shapes, one of which is a curved bridge with cables. Arch bridge is suitable for trident bridge because it has a long span. Through this thesis, the author tries to plan an alternative building over an existing bridge with a curve type. Preliminary planning data includes the total length of the existing bridge 150 m wide by 9 m. The planning method used is LRFD (Load Resistance Factor Design) and uses the Staad Pro v8i assist program. In this planning the author planned floor plates, elongated girders, transverse girders, parent girders, wind bonds, cables, joints and elastomers. From the results of the analysis obtained the structure of the building over the bridge for floor plates using the principal bones D10-200 and reinforcements for D13-200, the elongated steel gelagar profile WF 500 x 200 x 10 x 16, the steel transverse gelagar profile WF 800 x 350 x 16 x 36, the parent steel gelagar profile WF 700 x 300 x 13 x 24, steel steel bond double profile L250 x 250 x 35, for the dimensions of dyform cable D38, for laying using elastomer size 120 cm long, width 120 cm, height 26 cm

Evaluation of Site Variability Effect on the Geotechnical Data and Its Application

Abstract This study focused on evaluating the laboratory measurement errors and site variability due to soil deposition and operator using the following tests: unconsolidated-undrained (UU), Atterberg limits, small direct shear, and California bearing ratio (CBR) tests. Four clay soils with different plasticity indexes (PIs) were tested in the laboratory (PI = 11, 21, 38, 53), in addition to sandy soil and 3 aggregate base materials. Five different operators tested three specimens for each soil type to investigate the effect of operator on testing results. The maximum coefficient of variation (COV) data due to operator were 10.9 %, 7.8 %, 18.2 %, 16.9 %, 19.5 %, and 15.6 % for UU, liquid limit, plastic limit, plasticity index, direct shear, and CBR tests, respectively. The effect of operator and equipment on field testing results was evaluated using 28 cone penetration tests (CPTs) points performed in the same site at different times by two contractors. The spatial variability of CPT data was evaluated for each contactor and both combined. The values of COV for CPT data were different for the two contractors. The average COVs of pile design method and site variability were used to calibrate the Load Resistance Factor Design (LRFD) resistance factor, Φ, which showed high value for lower variability data, and vice versa for high variability data. The operator and equipment variabilities caused Φ to reach 0.24 for CPT data. In addition, the standard penetration test (SPT) and unconfined compressive strength test (qu) were collected from 21 borings and used to evaluate site variability. The value of Φ increased from 0.41, when COV of pile design method was only included, to 0.55, when site variability was included for SPT data. The same scenario was done for qu, in which Φ was increased from 0.34 when including COV of pile design method only to 0.39 when using the average COV of both method and site.

Design and structural analysis of an interprovincial bus applying the LFRD method

The research is aimed at the body industry specifically of a passenger transport bus which was subjected to a static analysis according to the requirements determined by the standard NTE INEN 1323:2009 and applying the Load Resistance Factor Design (LRFD) method for the different load combinations allowing to verify the resistance of the structure and its maximum deformation, according to the parameters allowed by the standard; the frontal impact according to the test conditions according to international standards of European New Car Assessment Program (Euro-NCAP) by means of the Finite Element Method (FEM), in order to determine the behavior of the body in case of a possible collision; the aerodynamics of the bodywork with the Computational Fluid Dynamics (CFD) software and in the wind tunnel in order to validate the results obtained in the software with reality, for this process the geometry of the bodywork was evaluated by printing a 3D prototype on a scale of 1:200, which resulted in a body conformed by a deflector presenting a higher lift coefficient, reduction of turbulence zones and optimum drag coefficient according to the norm.

The flexural buckling comparison between open and close cross sections in high column structure

Selection a cross-section of column on building construction needs to keep on a constant review to flexural buckling. The flexural buckling of column affects construction behavior overall. The aim of this study is comparing open and close of a cross-section column profile against flexural buckling. The hollow and pipe are representing close cross-sectional column profiles while I and T profiles are other represent. All profiles used the same material and properties, 400 Mpa of tensile strength and 740 mm2 area of cross-sectional. The high of column was 24 m which, both ends be fixed. Load Resistance Factor Design (LRFD)- SNI 1729:2015 method was applied to analyze the flexural buckling. The T profile was a control to determine percentage of column slender other profiles. The result showed that the slender was 53.43%, 75.57%, and 86.67% for hollow, pipe, and I respectively to T profile. The study indicates that the high column and inertia of cross-sectional were important role in flexural buckling failure.

LRFD for Lateral-Torsional Buckling Resistance of Cellular Beams

Cellular beams are those that present sequential web openings along the span, and are produced by thermal cutting and welding. Studies addressing the lateral-torsional buckling resistance curve of cellular beams according to the American standard are scarce. The objective of the present study is to investigate the lateral-torsional resistance in cellular beams, considering the Load and Resistance Factor Design. To this end, geometrical and material nonlinear analyses are conducted. The cellular beams are simply supported, with fork supports at the ends, and subjected to three types of loading: uniform bending, mid-span concentrated load and uniformly distributed loads. The geometric parameters of cross section and unrestrained length are varied. Results are compared with the nominal and design flexural strength. Failure modes are associated with non-dimensional lateral-torsional stiffness. Considering the application of uniform bending moment, failure modes such as LTB and WDB + LTB occurred. In contrast, considering the presence of shear stress, failure modes such as the Vierendeel mechanism, WPB, and WPB + LTB occurred. It was concluded that when compared with the numerical model results, the design flexural strength was ineffective under inelastic buckling regime, a situation in which interaction of modes of failure can occur. When considering only the pure lateral-torsional bucking, the Load Resistance Factor Design variation was observed. This variation presented an average value equal to 0.83, differing from the procedure in question by approximately 7.8%.

Desain Ulang Balok dan Kolom Komposit

The aim of this study is to redesign the beams and columns of reinforced concrete into a composite structure of Women's Empowerment and Child Protection Agency to derive a comparison of strength and efficiency between concrete-steel composite structures and reinforced concrete structures without changing the layout of columns and beams in the initial planning. LRFD (Load Resistance Factor Design) method and SAP2000 ver.14 as a tool were used in this study. The design was based on Indonesian Standard Regulation. The concrete strength (f’c) and steel strength ( were25 MPa and 250 MPa, respectively. In this study, steel profile BJ 37of WF (400 x 400 x 21 x 21) mm was used for beam and WF (400 x 400x 30 x 50) mm with concrete cross section (500 x 500) mm for column. The results of redesign composite structure for three-story building with the designed steel profile is fulfilled the strength requirements. The obtained maximum moment of beam and column are 36789,36 kg.cm and 43942,2 kg.cm, respectively. The used of composite material is 76,925% more expensive than reinforced concrete material.

A basic study on the application of LRFD in “the technical standard for port and harbour facilities in Japan”: a case of gravity type quay wall in a persistent design situation

ABSTRACTThe Partial Factor Method (PFM) based on the Level 1 reliability design method was introduced in 2007 to the Technical Standards for Port and Harbour Facilities (TSPHF-2007) in Japan. After nearly 10 years of practical use of TSPHF-2007, the design standard has been revised based on requests from the practitioners who recommend the transition from the PFM to the Load Resistance Factor Design (LRFD). In this paper, we discuss the setting method of the target failure probability to determine the partial factors based on code calibration. Furthermore, we examine the impacts of implementing the LRFD concept to the TSPHF by taking the sliding and overturning of a gravity type quay wall as an example to represent port and harbour facilities. We found no practical difference in caisson width derived using the LRFD and the PFM, whereas the degree of matching of the target failure probability was somewhat more precise for the PFM. This finding indicates that the LRFD is a more reasonable design method than the PFM in terms of the simplicity of the performance function itself and the ease of engineering interpretation during the design procedure.

Analysis and Design of Crane Beam of Experimental Power Plant Turbine Building

The turbine building is one of the main buildings in the experimental power plant (RDE). Turbine and condenser generators are the main components of the turbine building. The total weight of the generator and condenser is about 80 tons. It is estimated that the toughest parts of turbines and condensers are about 20 tons. The turbine building will be equipped with an overhead crane double girder. The benefits of cranes are as lifting equipment to assist the installation and maintenance of generators and condensers. The purpose of this paper is to design and analysis of the planned RDE turbine beam crane building. The method used is Load Resistance Factor Design or called LRFD methods. Some of the standards used include AISC Design Guide 7 second edition and CISC Crane Guide second edition. Based on the basic drawing of the turbine building design, the distance of the crane supporting column is 14 meters. It is planned that the total length of the girder crane is 13 meters. Weight hoist and trolley 2,950 kg and double girder 10,120 kg selected from one vendor crane product. The results of the calculations and checks show that the W shape with Cap Chanel W27x84 C15x33.9 is safe to used.

Reliability-Based Water Quality Assessment with Load Resistance Factor Design: Application to TMDL.

Effective load reduction strategies rely on an accurate Total Maximum Daily Load (TMDL) calculation, which quantifies contaminant loading from various sources. There is a wide range of methods to consider uncertainties in TMDLs: from simple, conservative assumptions regarding factors that contribute to the TMDL required margin of safety (MOS), to probability-based approaches such as Monte Carlo simulations, which explicitly quantifies TMDL uncertainty. In this paper the authors adapt the Load Resistance Factor Design (LRFD), a rigorous, reliability-based framework, to water quality assessment and the TMDL process. The LFRFD replaces the lumped MOS with design factors that reflect the magnitude and distribution of uncertainty among the various contaminant loads. In addition, it produces load reduction estimates to meet management objectives with a contaminant-specific frequency-based target. The LRFD is computationally efficient and flexible in that, to compute the design factors, the procedure can utilize: measurement data, analytical solutions or model simulation results, as well as full or marginal probability distributions.

Estimation of Pile Setup and Incorporation of Resistance Factor in Load Resistance Factor Design Framework

AbstractSoil setup is defined as the increase in axial resistance of driven piles after end of driving (EOD). Very recently, over the last five years, the time-dependent increase in axial resistanc...

School based optimization algorithm for design of steel frames

In this paper, a school-based optimization (SBO) algorithm is applied to the design of steel frames. The objective is to minimize total weight of steel frames subjected to both strength and displacement requirements specified by the American Institute of Steel Construction (AISC) Load Resistance Factor Design (LRFD). SBO is a metaheuristic optimization algorithm inspired by the traditional educational process that operates within a multi-classroom school. SBO is a collaborative optimization strategy, which allows for extensive exploration of the search space and results in high-quality solutions. To investigate the efficiency of SBO algorithm, several popular benchmark frame examples are optimized and the designs are compared to other optimization methods in the literature. Results indicate that SBO can develop superior low-weight frame designs when compared to other optimization methods and improves computational efficiency in solving discrete variable structural optimization problems.

ANALYSIS AND DESIGN USING BEAM CONSTRUTION OF THE PELITA BANGSA SCHOOL IN THE CIREBON CITY

ABSTRACT The success of the development from an area, which can be seen from the education level of the population. Increasingly developed education level of the population, it will be bring to the level of welfare for the population. Pelita Bangsa School Cirebon is a private school which has a ladder Play Group, Kindergarten, Elementary School, Junior High School and Senior High School, which is located in the city of Cirebon at the address on Terusan Laut Arafuru Street Blok A1 kavling . 6-7 Cirebon 45131 West Java. The additional building facilities of Pelita Bangsa School will be investigated in this thesis which is about structural analysis and design using steel material with LRFD (Load Resistance Factor Design) system. Analyze and design the construction of Pelita Bangsa School building with design code SNI-1729-2015 for building steel structures, SNI-1727-2013, PPPURG 1987 for loads and then SNI-1726-2012 for earthquake analysis. Analyze the structure with the help of SAP2000 (Structure Analysis Program 2000) software and design the building of Sekolah Pelita Bangsa using steel material. Keywords: Analysis and design structure, LRFD, steel material, SAP2000

설계법에 따른 풍화토 지반 얕은기초의 안전여유 비교

본 논문에서는 기존의 허용응력설계법(ASD)과 신뢰성해석에 기반을 둔 하중저항계수설계법(LRFD)과 유로코드의 부분안전계수설계법(PSFD)을 사용하여 풍화토지반 얕은기초의 전단파괴에 대한 지지력과 안전여유 산정결과에 대하여 비교 분석하였다. 얕은기초의 지지력에 영향을 주는 지반정수의 불확실성을 정량화하기 위하여 시공 및 설계용 평판재하시험 자료를 수집하고 확률 통계 분석을 통하여 극한지지력의 저항편향계수와 변동계수를 조사하였다. 국내 현장의 얕은기초 대표 단면 예에 대한 신뢰성해석(FORM)을 통하여 신뢰도지수를 구하고 지반정수의 확률변수가 전단파괴에 미치는 영향을 조사하기 위하여 확률변수의 민감도 분석을 하였다. ASD설계법, ASD설계법의 안전율에 대응하는 목표신뢰도 지수의 LRFD설계법, PSFD설계법을 사용하여 얕은기초 대표단면의 안정성 검토를 실시하여 산정된 각 설계법의 안전여유에 대하여 비교 검토를 실시하였다. In this paper bearing capacity and safety margin of shallow foundation on weathered soil ground against shear failure by using current design method of allowable stress design (ASD), load resistance factor design (LRFD) based on reliability analysis and partial safety factor design (PSFD) in Eurocode were estimated and compared to each other. Results of the plate loading test used in construction and design were collected and analysis of probability statistics on soil parameters affecting the bearing capacity of shallow foundation was performed to quantify the uncertainty of them and to investigate the resistance bias factor and covalence of ultimate bearing capacity. For the typical sections of shallow foundation in domestic field as examples, reliability index was obtained by reliability analysis (FORM) and the sensitivity analysis on soil parameters of probability variables was performed to investigate the effect of probability variable on shear failure. From stability analysis for these sections by ASD, LRFD with the target reiability index corresponding to the safety factor used in ASD and PSDF, safety margins were estimated respectively and compared.

Steel frame optimal design using MHBMO algorithm

Various deterministic and stochastic algorithms have been used as optimization tools in different engineering problems over the last decade. In this regard, the Modified Honey Bee Mating Optimization (MHBMO) algorithm may be considered as a typical swarm-based approach for optimizing numerous problems in engineering fields. In this paper, a design procedure based on the MHBMO technique was developed for discrete optimization of frames consisting W-shapes. The objective function in this research is to obtain the minimum weight of frames subjected to both strength and displacement requirements imposed by the American Institute for Steel Construction (AISC) and Load Resistance Factor Design (LRFD). Several frame examples from the literature were examined to verify not only the suitability of the design procedure but also the robustness of the MHBMO algorithm for frame structure design. The optimum results obtained by the MHBMO algorithm performs the best in comparison with other available techniques in the literature for all three steel frames. In conclusion, the results shows that the MHBMO algorithm is a powerful and applicable optimization method for design of frames consisting W-shapes.