Despite the advantages of combined vertical, moment, and horizontal (VMH) failure envelopes, serviceability was not adequately considered in previous studies, leading to the introduction of serviceability-based "design envelopes" in current research, as a complement to conventional failure envelopes. This study employs three-dimensional finite element analysis to develop design and failure envelopes for square raft and cubic embedded block foundations under VMH loading. The numerical investigation, validated against well-documented benchmarks, uses the Hardening Soil model with small-strain stiffness (HSS). The envelopes were developed using probe tests associated with the dominant system parameters: breadth (2.5 to 25 m), embedment depth to breadth ratio (1, 2, and 3), and c-ϕ subsoil relative density (loose, medium, and dense). The results demonstrate that serviceability limits often govern foundation design, since the design envelopes are significantly smaller than the associated failure envelopes. Embedment depth is identified as a significant parameter that influences the transition from base-bearing to three-dimensional resistance mechanisms and enhances moment and horizontal capacities. The study examines the relationship among foundation geometry, embedment ratio, and subsoil strength in shaping failure and design envelopes. Multivariate regression analysis was used to derive mathematical equations for ellipsoidal failure and design envelopes. Overall, the findings challenge the traditional safety-factor paradigm and highlight the need for displacement-based design methodologies in modern foundation systems.
Pre-Engineered Buildings (PEBs) have emerged as an efficient alternative to conventional steel structures due to their optimized material usage, reduced self-weight, and faster construction. This study presents a comparative analysis and design of tapered sections used in PEB portal frames to evaluate the influence of rafter break point location on structural behaviour. Five different structural models were developed using STAAD.Pro with identical geometry, loading conditions, and design criteria in accordance with ARE 800:2007, IS 875, and ARE 1893:2016. Among the five models, Model I was designed strictly based on bending moment requirements, while the remaining models were configured with varying rafter break points without strict adherence to moment-based design. The analysis includes evaluation of key parameters such as frame weight, bending moment, and support reactions under dead, live, wind, and seismic loads. The results indicate that Model I achieves the minimum structural weight, demonstrating efficient material utilization, whereas Model IV provides improved overall structural performance with better force distribution. It is observed that variation in rafter break point significantly affects bending moment distribution and structural efficiency, while support reactions remain nearly constant across all models. The study concludes that bending moment-based design is essential for achieving economical and optimized PEB structures, while intermediate tapering configurations can enhance overall performance.
Trupti Nandanwar, Mahendra Umare, Pritam Kandikurwar et al.· Journal of Structural Techno...· 0 citations
Reinforced concrete (RC) frame structures must undergo structural analysis as a first stage in their design to guarantee sufficient strength, stability, and serviceability when subjected to stresses. Engineers may now more efficiently and accurately model and analyze complicated structural systems in three dimensions because to advancements in structural analysis software. This research project details the STAAD-based structural analysis of a G+2 reinforced concrete frame. Professional V8i (SELECTseries 5) in action. Following the applicable Indian Standard standards, a three-dimensional analytical model was created with 87 structural members and 48 joints. The model accounted for the necessary material qualities, sectional dimensions, support conditions, and loads. All loads, whether dead or live, as well as the governing load combination of 1.5(DL + LL), were taken into account throughout the study. Support responses, bending moment, shear force, axial force, and vertical displacement were used to analyze the structural response. Selected STAAD results were used to confirm the computational model's correctness.Simplified manual computations grounded on classical structural analysis techniques were contrasted with Pro. The numerical model was shown reliable when the comparison revealed variances within acceptable engineering norms, with a maximum divergence of around 12%. All structural response characteristics fulfilled the serviceability standards defined in IS 456:2000, according to the study. According to the research, STAAD.Pro is a solid and efficient platform for conducting 3D analyses of reinforced concrete frame structures, which may greatly aid in engineering and structural design decisions.
JAKKANI CHAITHANYA, Mrs. A.V. ANJANI DEVI, Dr. B. SHARATH CHANDRA· International Journal of Eng...· 0 citations
This study proposes an integrated finite element methodology for evaluating and redesigning three critical subsystems of an XCMG XC740K skid-steer loader: the excavation attachment, the arm–bucket charging system, and the ROPS/FOPS operator protection cab. The components were reconstructed by reverse engineering and 3D scanning, modeled in CAD, and simulated in ANSYS Workbench/Mechanical under load cases derived from hydraulic parameters, soil–tool interaction, and international safety standards. The novelty of the work lies in applying a single FEM-based workflow to three interacting subsystems of the same compact machine, rather than optimizing isolated components independently. The original configuration showed critical effort concentrations in the cab and charging system. Localized geometric reinforcements and the use of high-strength and wear-resistant steels improved stiffness and safety margins in the excavation bucket, loading bucket, and ROPS/FOPS cab. However, the arm–quick coupler region remained the controlling weak point of the loading assembly, indicating the need for further redesign. The proposed approach provides a transferable computational framework for identifying structural vulnerabilities and prioritizing redesign actions in compact earthmoving machinery. Because the study is numerical, future experimental validation is required before certification or field implementation.
Diego Andrés Duque-Sarmiento, Gustavo Morocho, Juan José Molina-Campoverde et al.· Machines· 0 citations
This study investigates the blast response of reinforced concrete (RC) walls with varying boundary element (BE) configurations using a validated macro-model implemented in OpenSees. The model, based on embedded layered-shell elements, was verified against independent experimental and numerical benchmarks, demonstrating its ability to capture out-of-plane wall response and BE-specific behavior under blast loading. A systematic parametric investigation was conducted to evaluate the effects of BE placement and thickness, boundary conditions, reinforcement ratios, axial loading, and wall aspect ratios. Results show that a single central BE can enhance blast resistance by approximately 20%, while configurations with two BEs placed at 0.2 times the wall length (BW2) offer the highest efficiency among multi-BE layouts. Increasing the BE thickness to 35 cm provided the best balance of performance and material demand. Vertical web reinforcement significantly improved behavior, while horizontal reinforcement had a limited effect. Higher BE reinforcement ratios further reduced displacements, whereas axial loads reduced global displacement but led to increased localized compressive damage. Fragility curves revealed variations of up to 33.9% in collapse probability across configurations, particularly under moderate impulse levels. Pressure–impulse (P–I) diagrams were developed to enable rapid identification of performance thresholds for different BE arrangements. The findings offer design-oriented guidance for optimizing BE configurations in the blast design of RC walls, with direct implications for improving structural resilience in critical infrastructure.
Osama N. Ibrahim, M. Shedid, Tarek El-Hashimy· International Journal of Con...· 0 citations
This paper introduces a comprehensive mathematical framework for the design of rectangular reinforced concrete footings under axial load, surcharge, and biaxial moments, accounting for both fully and partially supported contact conditions. The proposed method presents a set of closed-form equations obtained via integration, which incorporate changes in soil pressure distribution resulting from eccentric loading. As the noble contribution, a key parameter named compression fraction λ, is added to differentiate between complete and partial soil-footing interaction. The model incorporates surcharge—a component overlooked in previous formulations—and generalizes the concept of equal width typically employed in footing design. Parametric analyses reveal the model’s responsiveness to fluctuations in vertical load, moments, soil bearing capacity, and aspect ratio. Results indicate consistent and rational tendencies, with the footing area expanding under elevated loads or diminished bearing capacity, and contracting with increased soil strength. A comparison with Landeros’s model demonstrates that the proposed method produces more economical designs, with footing area reductions of up to 49.91%. The incorporation of surcharge and the capacity to manage partial compression render the presented equations a reliable and effective resource for structural engineers pursuing precise and material-efficient footing designs under complex loading scenarios.
S. Rahman, Nusrat Nur Maisha, Abdul Moneim et al.· Discover Civil Engineering· 0 citations
Abstract This study evaluates the structural implications of adopting lightweight concrete (LC) in multistory buildings, with emphasis on columns – a configuration seldom examined. Three models of the same fourstory building – (i) all conventional concrete (CC), (ii) LC in slabs and beams (CLC), and (iii) LC in slabs, beams, and columns (LC) – were analyzed in AltoQi Eberick V10. Verifications followed NBR 6118 (ABNT 2023a); where NBR 6118 does not prescribe LC material properties, ACI 318-19 (ACI 2019) was used for the elastic modulus and EN 199211 (CEN 2004) for the densitybased tensile adjustment. Results show foundation loads decreased by up to 12.8% and total steel consumption by up to 13.7% with LC, while lateral displacements remained within code limits. Applying LC in columns increased the global instability index to γz = 1.10 yet retained a nonsway classification. The column case clarifies the tradeoff between weight reduction and increased deformability and provides codeanchored guidance for safe adoption in Brazilian practice. Overall, the findings indicate that LC is structurally viable and materially efficient for multistory buildings under NBR-based design, and highlight priorities for detailing and stiffness control when columns are also cast with LC.
Edmilson Roque da Silva, I. V. Fernandes, Marcos David dos Santos et al.· Anais da Academia Brasileira...· 0 citations