Abstract While reinforced concrete column–steel beam (RCS) joints are well-studied, the seismic performance of RCS frames incorporating floor slabs remains inadequately explored. This study extends previous experimental findings, developing and validating an OpenSees finite element model of an RCS frame with slabs against test data. The model accurately replicated hysteretic responses, with peak load and ductility errors within 5%. A parametric study quantified the effects of the axial compression ratio, concrete strength, beam flange/web thickness, and shear span ratio. The results demonstrate that increasing the concrete strength from C40 to C70 boosted the lateral bearing capacity by 45.45%. In contrast, a higher axial compression ratio increased the initial stiffness but accelerated the subsequent stiffness degradation. Furthermore, recalibrating the energy dissipation coefficient (β) in the Park–Ang damage model yielded an excellent correlation (R 2 = 0.994) between the simulated and experimental cumulative damage indices, providing a refined tool for seismic damage assessment.
Systems of building construction. Including fireproof construction, concrete construction
Abstract This study examined the influence of the water–binder ratio and calcium sulfoaluminate (CSA) cement replacement on the properties of fresh three-dimensional concrete printing (3DCP) materials and identified optimized mix proportions to enhance buildability. Experimental analyses included flowability tests, setting time evaluations, green strength assessments, extrusion pressure measurements, and printing tests. Buildability was evaluated using layer strain and interlayer bonding performance as key indicators, while statistical techniques were applied to develop a mixture design that maximized buildability and minimized the number of printing tests required. The experimental results showed that layer strain increased with a higher water–binder ratio and a lower CSA cement replacement ratio, and a similar trend was observed for interlayer bonding performance. The optimized mixture was determined using response surface methodology based on 13 experimental runs, yielding a water–binder ratio of 0.297 and a CSA cement replacement ratio of 3.88%. Verification results indicated that the optimized mixture exhibited superior buildability, with a mean relative error of 7.55% between the measured and predicted values, demonstrating close agreement between actual performance and predicted outcomes. These findings confirmed that the optimization process was effective and practically sound for enhancing the buildability of 3DCP materials.
Systems of building construction. Including fireproof construction, concrete construction
Valery G. Shamonin, Alexey V. Golkin, Stanislav A. Zuev
et al.
There is considered the possibility of solving the problem of optimal choice of evacuation exits along one or both sides of curved corridors, both sides of which are parts of an ellipse, for further minimizing the mixing of human flows (and, accordingly, preventing congestion during movement of people) during evacuation in case of fire or other emergencies. An algorithm for determining the optimal distribution of exits for narrow corridors is presented.
Systems of building construction. Including fireproof construction, concrete construction
Abstract This study investigated punching shear behavior in thin flat slabs (1500 × 1000 × 120 mm) with openings adjacent to edge columns, evaluating three shear reinforcement methods: bent bars, shear bands, and shear studs. Experimental testing of seven specimens demonstrated that shear studs provided optimal performance, enhancing the first cracking load by 10%, ultimate capacity by 4.74%, and energy absorption by 80.07% relative to the control specimen. In specimens with two symmetrically positioned openings resulting in 50% cross-sectional reduction, shear stud reinforcement preserved 86% of the control specimen's load-bearing capacity. Analysis against established design codes indicated that ACI, CSA, ECP, and NZS provisions reasonably predicted punching capacities, while Eurocode 2 equations yielded overestimations. Shear studs proved effective for strengthening slab-column connections with service openings. However, the findings are based on small-scale specimens, and further studies under varied loading conditions are needed.
Systems of building construction. Including fireproof construction, concrete construction
Asad Kareem, Syed Saqib Mehboob, Diyar Khan
et al.
Abstract Date palm fiber-reinforced concrete (DPFRC) has appeared as a promising alternative in the construction industry, offering an eco-friendly and sustainable solution to improve the mechanical properties of concrete. This comprehensive review delves into the extensive research conducted on DPFRC, exploring its potential applications, mechanical characteristics, and environmental benefits. The rationale of this review is based on the comparative analysis of DPF-reinforced concrete with various other fiber-reinforced concretes in terms of carbon footprint, sustainability, mechanical properties, ductility, acid attack and thermal conductivity. Furthermore, the review examines the influence of fiber content, aspect ratio, and orientation on the tensile (TS), flexural (FS), and compressive strength (CS) of DPFRC. DPF is responsible for a small increase in CS and a remarkable increase in TS and FS in concrete. The optimum content of 0.1–1% and the small length of fibers (<50 mm) is found to be optimum for maintaining CS and water absorption, while the percentage up to 5% is found to be significant for improving TS and FS. Apart from the mechanical characteristics, the review investigates the durability aspects of DPFRC, including resistance to shrinkage, cracking, and corrosion. High ductility and thermal insulation properties also make it an ideal candidate for specific infrastructure applications. Moreover, the review comparatively analyzed the sustainability implications of DPFRC, emphasizing its potential to mitigate carbon emissions, reduce waste from agricultural residues, and contribute to the circular economy. Case studies and practical applications of DPFRC in construction projects are also examined, showcasing its feasibility and effectiveness in real-world scenarios. Overall, this review provides valuable insights into the untapped potential of DPFRC, serving as a comprehensive resource for researchers, engineers, and practitioners seeking to harness the benefits of this innovative construction material.
Systems of building construction. Including fireproof construction, concrete construction
As labor shortages and productivity stagnation increasingly challenge the construction industry, automation has become essential for sustainable infrastructure development. This paper presents an autonomous payload transportation system as an initial step toward fully unmanned construction sites. Our system, based on the CD110R-3 crawler carrier, integrates autonomous navigation, fleet management, and GNSS-based localization to facilitate material transport in construction site environments. While the current system does not yet incorporate dynamic environment adaptation algorithms, we have begun fundamental investigations into external-sensor based perception and mapping system. Preliminary results highlight the potential challenges, including navigation in evolving terrain, environmental perception under construction-specific conditions, and sensor placement optimization for improving autonomy and efficiency. Looking forward, we envision a construction ecosystem where collaborative autonomous agents dynamically adapt to site conditions, optimizing workflow and reducing human intervention. This paper provides foundational insights into the future of robotics-driven construction automation and identifies critical areas for further technological development.
A. Rathnayake, Danny Murguia, Ashan Senel Asmone
et al.
Discontinuous work in construction refers to periods without resource or work continuity, leaving workers without designated locations to perform their tasks. Studies show in many activities idle durations are a significant portion of total work. Caused by poor production system design in projects, discontinuous work is a major cause of low trade productivity. This paper aims to identify factors affecting discontinuous work and quantify their impact. 346 datapoints (including 46 superstructure crews across 75 building levels in 10 multistorey buildings in London) were analysed using correlation and regression techniques. Data included crew size, batch size, activity type, work start and end dates. Results showed that reducing the batch size by increasing slab concrete pours per level minimised discontinuities by ensuring more available work locations. Synchronising the production rates of successive crews also reduced discontinuities by limiting idle time for faster crews. Surprisingly, although often considered a cause of discontinuities, out-of-sequence work had no statistically significant relationship with discontinuities. Possibly due to the constraints of superstructure work limiting the out-of-sequence work. Additionally, offsite construction methods exhibited greater variability in discontinuities compared to in-situ methods, likely due to clashes between in-situ activities happening at a different rate of work to offsite activities.
M. D. Utomo, Suryawan Murtiadi, S.PsiM.Si.PhD Taufik
The rapid development of the construction industry demands optimization in efficiency and sustainability principles. One approach that is increasingly being considered to address these challenges is the utilization of precast concrete systems. This research evaluates the impact of precast concrete structural system implementation on project performance, with a case study on the Kemah Tabernakel Church project in Pantai Indah Kapuk 2 (GKT-PIK2). Many factors can affect the performance of construction projects, including the 5M+T factors: Man, Measurement, Method, Material, Machine, and Time. The research uses a descriptive qualitative approach combined with quantitative analysis thru field observation, distribution of Likert-scale questionnaires, and expert interviews. Data analysis is performed using correlation tests and multiple linear regression with SPSS software to determine the significance of the impact of precast concrete structure system implementation. The research results indicate that the implementation of the precast system has a significant impact on improving project performance. The five dominant variables affecting performance are design changes, workforce competency, installation methods, tower crane usage, and timely delivery. These five factors have been proven to have a positive and linear relationship with overall project performance achievement. This research concludes that a precast concrete structural system designed according to SNI 9163:2023 regulations, and supported by appropriate technical and managerial strategies, is capable of improving project execution performance. The contribution of this research also provides practical implications in the form of technical recommendations to support the successful implementation of precast systems in multi-story building construction projects.
As global urbanization intensifies and seismic risks increase in densely populated regions, developing earthquake-resilient buildings has become a critical priority in structural engineering. This study provides a comprehensive analysis of advancements in seismic design methodologies, innovative materials, and smart technologies implemented between 2010-2023 across high-seismicity urban regions including California, Japan, Chile, New Zealand, and Turkey. Employing a problem-based research methodology, the investigation synthesizes performance data from 850 instrumented buildings across 45 major earthquakes (magnitude 6.0-9.0), laboratory testing of 120 structural components, and computational modeling of 5,000 building configurations. Results demonstrate that modern seismic design approaches—including base isolation, energy dissipation devices, and rocking wall systems—reduce structural damage by 60-85% compared to conventional fixed-base construction during major seismic events. Performance analysis reveals that buildings incorporating seismic isolation systems experienced peak inter-story drift reductions of 70-90% and floor acceleration reductions of 60-80% during the 2011 Christchurch and 2017 Mexico City earthquakes. Material innovations show that high-performance fiber-reinforced concrete (HPFRC) increases energy dissipation capacity by 300-400% compared to conventional concrete, while shape memory alloy (SMA) reinforcement maintains 95% of its original strength after experiencing 7% strain. Post-earthquake functionality assessments indicate that resilient buildings achieve 85-95% immediate occupancy ratings compared to 15-30% for conventional buildings following major seismic events. However, cost-benefit analysis reveals that advanced seismic technologies increase initial construction costs by 8-25%, though lifecycle cost savings from reduced downtime and repair needs yield benefit-cost ratios of 3.5-6.2 over 50-year building lifespans. Implementation barriers include code compliance challenges (affecting 35% of innovative systems), skilled labor shortages (60% of contractors lack specialized training), and public perception gaps regarding cost versus safety trade-offs. This research concludes that while seismic resilience technologies have advanced substantially, their widespread urban implementation requires integrated approaches combining performance-based design, regulatory innovation, workforce development, and economic incentives to create truly earthquake-resilient cities.
Prestressed concrete transfer slabs, or prestressed transfer plates, are emerging as an efficient structural solution for high-rise buildings, particularly at transfer floor levels. Widely adopted in Malaysia, Hong Kong, and China, these systems effectively redistribute shear wall loads from tower blocks to the broader column grids of podium structures below. Compared to conventional transfer beam systems, prestressed transfer plates offer significant advantages, including cost efficiency, simplified formwork, streamlined reinforcement detailing, and an aesthetically clean soffit. A key innovation is their ability to be cast in stages, where the initial cast is prestressed to support subsequent pours, dramatically reducing the need for extensive temporary formwork. This paper explores the evolution, structural behavior, and global trends in prestressed transfer plate design. Practical guidelines for preliminary sizing, reinforcement estimation, and finite element modeling are provided. The discussion highlights the interaction between shear walls and transfer plates under gravity loads, and the implications of multi-stage casting. The findings demonstrate that prestressed transfer plates are a viable alternative to conventional systems, offering economic and construction efficiency benefits for modern high-rise structures.
Saad A. Yehia, Sabry Fayed, Mohamed H. Zakaria
et al.
Abstract The contribution of shear resisted by flanges of T-beams is usually ignored in the shear design models even though it was proven by many experimental studies that the shear strength of T-beams is higher than that of equivalent rectangular cross-sections. Ignoring such a contribution result in a very conservative and uneconomical design. Therefore, the aim of this research is to investigate the capability of machine learning (ML) techniques to predict the shear capacity of reinforced concrete T-beams (RCTBs) by incorporating the contribution of the flange. Five machine learning (ML) techniques, which are the Decision Tree (DT), Random Forest (RF), Gradient Boosting Regression Tree (GBRT), Light Gradient Boosting Machine (LightGBM), and Extreme Gradient Boosting (XGBoost), are trained and tested using 360 sets of data collected from experimental studies. Among the various machine learning models evaluated, the XGBoost model demonstrated exceptional reliability and precision, achieving an R-squared value of 99.10%. The SHapley Additive exPlanations (SHAP) approach is utilized to identify the most influential input features affecting the predicted shear capacity of RCTBs. The SHAP results indicate that the shear span-to-depth ratio (a/d) has the most significant effect on the shear capacity of RCTBs, followed by the ratio of shear reinforcement multiplied by the yield strength of shear reinforcement ( $${\rho }_{{\text{v}}}{f}_{{\text{yv}}}$$ ρ v f yv ), flange thickness ( $${h}_{{\text{f}}}$$ h f ), and flange width ( $${b}_{{\text{f}}}$$ b f ). The accuracy of the XGBoost model in predicting the shear capacity of RCTBs is compared with established codes of practice (ACI 318-19, BS 8110-1:1997, EN 1992-1-2, CSA23.3-04) and existing formulas from researchers. This comparison reinforces the superior reliability and accuracy of the machine learning approach compared to traditional methods. Furthermore, a user-friendly interface platform is developed, effectively simplifying the implementation of the proposed machine-learning model. The reliability analysis is performed to determine the value of the resistance reduction factor (ϕ) that will achieve a target reliability index ( $${\beta }_{T}$$ β T = 3.5).
Systems of building construction. Including fireproof construction, concrete construction
We consider arbitrary bounded discrete time series originating from dynamical system with recursivity. More precisely, we provide an explicit construction of recurrent neural networks which effectively approximate the corresponding discrete dynamical systems.
Abstract Concrete is a highly versatile construction material, not only for the reason that it has excellent properties in terms of structural performance, building physics, availability and price, but also because it can be moulded into virtually any shape regardless of its geometric complexity. However, even though current digital design tools allow to effortlessly design and calculate structures, which are exploiting these properties, this potential remains all too often unrealized. This is due to the fact that geometrically complex concrete structures require expensive, one-of-a kind formwork, which can often not be reused or even recycled. Consequently, the current practice for producing non-standard curvilinear architecture in reinforced concrete is neither ecologically sustainable nor economically feasible for a broader range of architectural typologies. Additive Manufacturing (AM) processes, like 3D printing with concrete, on the other hand, currently struggle with the integration of structural reinforcement, limiting the technique to predominantly compression-loaded applications. This research addresses both issues and proposes Mesh Mould, a robotic fabrication process that unifies concrete formwork and structural reinforcement, and hence potentially reduces formwork waste and construction costs for non-standard reinforced concrete constructions. The development of a fully automated robotic fabrication process involved various research disciplines, including architecture, material science, mechanical engineering, robotics as well as civil engineering. This paper describes the technological developments of the Mesh Mould construction system that were necessary to meet the challenges of 1:1 construction. The results are demonstrated in a final loadbearing structure, the Mesh Mould wall of the DFAB HOUSE on NEST.
Carbon dioxide is produced during the manufacture of normal Portland cement; however, this gas may be minimized by utilizing ground granulated blast furnace slag (GGBFS). When planning and constructing concrete buildings, compressive strength (f c ), a crucial component of concrete mixtures, is a need. It is essential to assess this GGBFS-blended concrete property precisely and consistently. The major objective of this research is to provide a practical approach for a comprehensive evaluation of machine learning algorithms in predicting the f c of concrete containing GGBFS. The research used the Equilibrium optimizer (EO) to enhance and accelerate the performance of the radial basis function (RBF) network (REO) and support vector regression (SVR) (SEO) analytical methodologies. The novelty of this work is particularly attributed to the application of the EO, the assessment of f c including GGBFS, the comparison with other studies, and the use of a huge dataset with several input components. The combined SEO and REO systems demonstrated proficient estimation abilities, as evidenced by coefficient of determination (R2) values of 0.9946 and 0.9952 for the SEO’s training and testing components and 0.9857 and 0.9914 for the REO, respectively. The research identifies the SVR optimized with the EO algorithm as the most successful system for predicting the f c of GGBFS concrete. This finding has practical implications for the construction industry, as it offers a reliable method for estimating concrete properties and optimizing concrete mixtures.
In this paper, we construct the moduli spaces of filtered $G$-local systems on curves for an arbitrary reductive group $G$ over an algebraically closed field of characteristic zero. This provides an algebraic construction for the Betti moduli spaces in the tame nonabelian Hodge correspondence for vector bundles/principal bundles on noncompact curves. As a direct application, the tame nonabelian Hodge correspondence on noncompact curves holds not only for the relevant categories, but also for the moduli spaces.
The coset construction is a tool for systematically building low energy effective actions for Nambu-Goldstone modes. This technique is typically used to compute time-ordered correlators appropriate for $S$-matrix computations for systems in their ground state. In this paper, we extend this technique to the Schwinger-Keldysh formalism, which enables one to calculate a wider variety of correlators and applies also to systems in a mixed state. We focus our attention on internal symmetries and demonstrate that, after identifying the appropriate symmetry breaking pattern, Schwinger-Keldysh effective actions for Nambu-Goldstone modes can be constructed using the standard rules of the coset construction. Particular emphasis is placed on the thermal state and ensuring that correlators satisfy the KMS relation. We also discuss explicitly the power counting scheme underlying our effective actions. We comment on the similarities and differences between our approach and others that have previously appeared in the literature. In particular, our prescription does not require the introduction of additional ``diffusive'' symmetries and retains the full non-linear structure generated by the coset construction. We conclude with a series of explicit examples, including a computation of the finite-temperature two-point functions of conserved spin currents in non-relativistic paramagnets, antiferromagnets, and ferromagnets. Along the way, we also clarify the discrete symmetries that set antiferromagnets apart from ferromagnets, and point out that the dynamical KMS symmetry must be implemented in different ways in these two systems.
A construction sequence for a graph is a listing of the elements of the graph (the set of vertices and edges) such that each edge follows both its endpoints. The construction number of the graph is the number of such sequences. We determine this number for various graph families.