Saingam, Panumas

Preferred name

Saingam, Panumas

Main Affiliation

School of Engineering

panumas.sa@kmitl.ac.th

Now showing 1 - 10 of 65

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Prediction of Stress–Strain Curves for HFRP Composite Confined Brick Aggregate Concrete under Axial Load
(2023-02-01)
Saingam, Panumas
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Ejaz, Ali
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Ali, Nazam
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Nawaz, Adnan
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Hussain, Qudeer
Recently, hemp-fiber-reinforced polymer (HFRP) composites have been developed to enhance the strength and ductility of normal and lightweight aggregate concrete along with recycled brick aggregate concrete. In addition, both experimental and analytical investigations have been performed to assess the suitability of the existing strength and strain models. However, the theoretical and analytical expressions to predict the stress–strain curves of HFRP-confined concrete were not developed. Therefore, the main objective of this study was to develop analytical expressions to predict the stress–strain curves of HFRP-confined waste brick aggregate concrete. For this purpose, a new experimental framework was conducted to examine the effectiveness of HFRP in improving the mechanical properties of concrete constructed with recycled brick aggregates. Depending on the strength of the concrete, two groups were formed, i.e., Type-1 concrete and Type-2 concrete. A total of sixteen samples were tested. The ultimate compressive strength and strain significantly increased due to HFRP confinement. Improvements of up to 272% and 457% in the ultimate compressive strength and strain were observed due to hemp confinement, respectively. To predict the ultimate compressive strength and strain of HFRP-confined concrete, this study investigated several existing analytical stress–strain models. Some of the strength models resulted in close agreement with experimental results, but none of the models could accurately predict the ultimate confined strain. Nonlinear regression analysis was conducted to propose expressions to predict the ultimate compressive strength and strain of HFRP-confined concrete. The proposed expressions resulted in good agreement with experimental results. An analytical procedure was proposed to predict the stress–strain curves of hemp-confined concrete constructed by partial replacement of natural coarse aggregates by recycled fired-clay brick aggregates. A close agreement was found between the experimental and analytically predicted stress–strain curves.
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Predicting Flexural Strength of FRP-Strengthened Waste Aggregate Concrete Beams with Machine Learning: A Step Towards Sustainability
(2026-04-01)
Sangthongtong, Arissaman
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Chatveera, Burachat
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Sua-iam, Gritsada
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Nawaz, Adnan
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Mehmood, Tahir
Using waste materials in the manufacture of concrete has many environmental advantages. However, it can be difficult to estimate structural performance, especially when beams are reinforced with fiber-reinforced polymers (FRP). In order to provide a data-driven approach to sustainable structural design, this work explores the use of machine learning (ML) approaches to forecast the flexural strength of FRP-strengthened waste aggregate concrete beams. A total number of 92 experimental datasets were used to develop and assess four ML algorithms: Random Forest (RF), Decision Tree (DT), Neural Network (NN), and Extreme Gradient Boosting (XGBoost). Regression plots, Taylor diagrams, statistical measures (R2R^2R2, RMSE, MAE, MSE), and explainable AI (XAI) tools, including SHAP, LIME, and partial dependence plots (PDPs), were used to evaluate the model’s performance. RF outperformed NN in terms of predictive accuracy, while XGBoost exhibited similar performance to RF. The most significant predictors, according to a SHAP analysis, were beam length and fiber length, with the lower followed by steel tensile strength, fiber width, and concrete compressive strength. LIME offered local interpretability for individual predictions, but PDPs demonstrated optimal parameter ranges and a nonlinear feature strength relationship. The findings provide engineers with a strong decision-support tool for designing green infrastructure, since they show that ensemble-based models can accurately represent the intricate, nonlinear dynamics controlling flexural behavior in sustainable FRP-strengthened waste aggregate concrete beams.
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Cyclic Behavior of Different Connections in Precast Concrete Shear Walls: Experimental and Analytical Investigations
(2023-06-01)
Yooprasertchai, Ekkachai
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Wiwatrojanagul, Pongsak
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Saingam, Panumas
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Khan, Kaffayatullah
This study investigated the grouted sleeve splices and corrugated duct splices between shear walls and footing. In this regard, three shear walls were experimentally tested. One wall was cast monolithically with the foundation (RCWS), whereas two walls were precast. One wall was connected to the foundation using splice sleeves (PGWS), and another with corrugated duct splices (PCWS). All the walls were tested under reverse cyclic loading and a constant axial load. It was observed that the performance of specimen PGWS was controlled by rocking, and a premature connection loss was observed at one of the grouted sleeve splices. The hysteretic performance of specimen PCWS was close to that of specimen RCWS, whereas extensive pinching was observed in the hysteretic response of specimen PGWS. The peak load, ductility, secant stiffness, and energy dissipation of specimens RCWS and PCWS were in good agreement, whereas the energy dissipated by specimen PGWS was considerably lower than the corresponding values of specimens RCWS and PCWS. Nonlinear fiber-based modeling in OpenSees was performed using SFI-MVLEM elements. The predicted hysteretic response of the OpenSees model was in close agreement with the experimental response.
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Influence of Recycled Plastic Incorporation as Coarse Aggregates on Concrete Properties
(2023-04-01)
Ali, Khawar
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Saingam, Panumas
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Qureshi, Muhammad Irshad
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Saleem, Shahzad
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Nawaz, Adnan
Plastic waste has increased significantly in recent years as a result of fast population growth and urbanization. Studies on the incorporation of plastic aggregates as a substitution for natural aggregates in concrete are needed to successfully reduce both adverse environmental impact and the depletion of natural resources. The objective of this research was to investigate the use of plastic as a partial substitution for natural coarse aggregates in concrete. For this purpose, seven concrete mixes were produced using 0, 10, 15, and 20% plastic coarse aggregates to replace natural aggregates with and without silica fume of similar replacement levels with cement. Fresh density, workability, compressive strength, splitting tensile strength, stress–strain response, and Poisson’s ratio were observed to study the fresh as well as hardened properties of concrete mixtures. Indoor and outdoor thermal performance and thermo-gravimetric analysis were also investigated. The results revealed that the plastic aggregates’ incorporation improved the workability of concrete; however, it negatively influenced the fresh density and mechanical properties of concrete. The compressive and tensile strengths of plastic aggregate concrete without silica fume were reduced by 32 and 33%, respectively. The reduction in strength could be associated with the smooth texture of plastic aggregates. The addition of silica fume with plastic aggregates resulted in denser concrete and improved mechanical properties. In general, the performance of plastic aggregates as a partial replacement for natural aggregates was satisfactory, which suggests their possible use to produce eco-friendlier concrete.
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Enhancing the flexural response of RC one-way slabs using low cost fiberglass chopped mat sheets and anchors
(2025-07-01)
Yooprasertchai, Ekkachai
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Ejaz, Ali
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Chatveera, Burachat
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Sua-iam, Gritsada
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Hussain, Qudeer
This study experimentally evaluated the effectiveness of Carbon Fiber Reinforced Polymer (CFRP) and Fabric Cementitious Matrix (FCSM) sheets in enhancing the structural performance of one-way reinforced concrete slabs under three-point bending. Fourteen slabs were tested, considering key variables such as the number of FCSM sheets, type, size, and spacing of anchors to mitigate debonding. Results revealed that slabs strengthened with FCSM sheets and epoxy anchors demonstrated peak capacity improvements of up to 151 %, while mechanical anchors yielded a peak improvement of 95 %. Epoxy anchors also enhanced energy dissipation by up to 222 %, surpassing the 76 % maximum improvement observed with mechanical anchors. However, slabs with more than two FCSM layers required robust anchorage systems to maintain increased capacity without significant drops due to debonding. Slabs with epoxy anchors showed higher peak capacities but were more prone to abrupt post-peak losses than those with mechanical anchors. These findings underline the critical role of anchor type and configuration in optimizing the flexural and energy dissipation performance of strengthened slabs, providing valuable insights for sustainable and effective retrofitting strategies. Finite element modeling of slabs strengthened with FCSM, assuming no debonding, was carried out using ATENA software. The adopted modeling approach yielded slightly overestimated predictions of ultimate loads. As this represents initial research in the field, further investigations are recommended to develop more accurate and refined constitutive laws for FCSM to enhance the reliability of FEM simulations.
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Influence of natural fiber rope wrapping techniques on the compressive response of recycled aggregate concrete circular columns
(2023-09-01)
Chaiyasarn, Krisada
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Poovarodom, Nakhorn
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Ejaz, Ali
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Ng, Anne W.M.
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Hussain, Qudeer
The utilization of recycled waste in the production of new concrete raises significant concerns regarding the quality of the resulting concrete. One prominent drawback of recycled aggregate concrete (RAC) is its inferior mechanical properties compared to natural aggregate concrete. In this study, we examine the impact of hemp fiber rope (HFR) confinement on improving the compressive stress-strain behavior of RAC, specifically using recycled brick aggregates from fired-clay solid bricks (RAC-FCSB) as a partial substitute for natural coarse aggregates. Furthermore, we explore and compare the effectiveness of HFR confinement in the form of strips versus fully wrapped confinement. To conduct the experiments, a comprehensive framework was developed, involving a total of 32 cylindrical specimens. The parameters of interest included the configuration of HFR confinement (strips or full wrapping), the number of HFR layers, and the inherent strength of the concrete. The results indicate that HFR strips can significantly enhance the compressive stress-strain response. However, their performance falls short when compared to the fully wrapped HFR confinement. Nonetheless, HFR strips were able to enhance the peak compressive stress and strain of RAC-FCSB up to 204% and 190%, respectively. The second part of the study investigated the performance of existing models of HFR confinement in predicting the peak compressive stress and strain of RAC-FCSB. The deficiencies in existing models were highlighted, and new models based on non-linear regression analysis were proposed to accurately predict the peak compressive stress and strain of HFR-confined RAC-FCSB.
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Advancing Masonry Engineering: Effective Prediction of Prism Strength via Machine Learning Techniques
(2026-04-01)
Saingam, Panumas
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Chatveera, Burachat
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Nawaz, Adnan
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Ali, Muhammad Hassan
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Choudhary, Sandeerah
Masonry buildings have shaped construction history since about 6500 BCE. They offer durability, strength, and cost effectiveness, especially in developing countries. Yet assessing compressive strength during construction remains challenging due to the constituent materials soil, cement, and stone, complicating standardization worldwide. In the present study, an innovative model based on a machine learning algorithm is put forth to predict the compressive strengths of prisms. Some important factors considered as input to the algorithm based on traditional methods are the brick and mortar strengths, prism geometry, mortar bed thickness, and empirically derived height-to-thickness (t) (h/t) ratios. Three different ANN algorithms are coded and trained on the input data, and they are based on the Levenberg–Marquardt algorithm, the resilient backpropagation algorithm, and the conjugate gradient algorithm. The optimal ANN model trained using the conjugate gradient Polak–Ribière algorithm (traincgp) achieves superior performance, with R<sup>2</sup> = 0.9881, R<sup>2</sup> = 0.9927, RMSE = 0.9914 MPa, MAE = 0.6039 MPa, MAPE = 20.9141%, VAF = 0.9881, and WI = 0.9970. Sensitivity analysis shows the height-to-thickness (h/t) ratio is the dominant influence on compressive strength, consistent with structural mechanics. The primary contributions are the systematically curated, richly parameterized dataset and its use to produce robust, physically interpretable predictions with established ANN methods.
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Modeling and comparative analysis of sustainable cotton rope confinement: Full vs. STrip wrapping for enhanced concrete strength and ductility
(2025-07-01)
Saingam, Panumas
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Gadagamma, Chaitanya Krishna
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Hussain, Qudeer
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Hlaing, Hnin Hnin
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Suwannatrai, Rawirot
The rise of natural FRPs as ecological alternatives to synthetic ones has highlighted the need for studies on partial confinement using cotton ropes, which offer cost-effective, low-carbon solutions with high rupture strain. Unlike full confinement, partial confinement through cotton rope strips can efficiently strengthen deteriorated concrete sections with reduced material usage. Despite possessing several advantages, the partial confinement by cotton on concrete has not been investigated. This study addresses the gap by investigating the performance of cotton rope strips and developing analytical models to predict their structural impact. This study tested cylindrical concrete specimens of two strengths, strengthened with cotton rope in either complete wrapping (Group 1) or strip wrapping (Group 2). Each group was further divided by concrete strength and included one unstrengthened specimen, and three strengthened with one, two, or three layers of cotton rope. Experimental results revealed that cotton rope wraps effectively confined the concrete, enhancing load-bearing capacity and improving ultimate compressive strength by 9.97–152.10 % and ultimate strain by 188.00 % to 1488.89 %. The compressive stress vs. strain behavior exhibited an initial stiff elastic ascent followed by a parabolic transition. The second branch of the response, either ascending or descending, was significantly improved with an increased confinement ratio. Type-I failure was characterized by an ascending second branch in the compressive stress vs. strain curve, while Type-II failure exhibited a descending second branch. Four specimens demonstrated Type-I failure (L-2F, L-3F, H-3F, and L-3S), predominantly in full configurations and with lower unconfined compressive strength. The modulus of the second branch improved with an increased confinement ratio, transitioning from Type-II to Type-I failure near a ratio of approximately 0.50. Regression analysis provided equations of various key points along the compressive response with R² values greater than 0.90, highlighting a strong dependence on the confinement ratio. The Popovics model effectively predicted the first part of the compressive response, with predicted curves closely matching experimental results.
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Effect of para-wood ash and calcium carbonate on the properties of eco-friendly self-compacting mortar reinforced with electronic waste fibers
(2024-10-15)
Makul, Natt
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Hussain, Qudeer
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Nawaz, Adnan
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Saingam, Panumas
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Sua-iam, Gritsada
This paper deals with reducing CO<inf>2</inf> emissions from cement production and finding alternative uses for electronic waste (E-waste) fibers in some innovative applications in self-compacting mortar (SCM). In the present research, an attempt has been made to establish the optimum incorporation of E-waste fiber into SCM by varying the fiber content from 5 % to 25 %, combined with para-wood ash and calcium carbonate as supplementary cementitious materials. In this laboratory study, the mix design had a constant water-to-powder ratio of 0.35 and a cement content of 550 kg/m³. Additionally, 20 % of the cement volume was replaced by 10 % para-wood ash and 10 % calcium carbonate. The results indicated a continuous increase of the mini-slump values from 255 mm for the control mix to 270 mm for the mix with the highest fiber content. Mini V-funnel flow times increased from 3.63 to 8.83 s as the fiber content increased. Lower fiber contents of 5 % improved compressive strength because they had a reinforcing role in the matrix of SCM besides the microcrack-bridging role. Higher contents of 10–25 % decreased the strength due to the clustering of fibers and resulting voids. SEM analysis at 28 days showed increased voids with higher percentages of E-waste fibers and para-wood ash alone. The results underline that optimizing fiber content is critical in balancing workability and mechanical properties, and 5 % e-waste fiber content can be considered optimal for enhancing the performance of SCM. This work also creates part of sustainable construction practice with the green solution required to reduce CO<inf>2</inf> emissions and work accumulation against E-waste.
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Seismic Retrofit of Shear Wall Medium-Rise RC Building with Buckling-Restrained Braces
(2024-01-01)
Hlaing, Hnin Hnin
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Suwannatrai, Rawirot
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Tammajak, Nontaphat
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Kriangkriatkong, Phusana
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Nakkahnong, Apisak
Thailand was impacted by the earthquake both directly and indirectly. Many structures in Chiang Rai were damaged by the large Mae Lao earthquake in 2014. This makes the government recognize how crucial it is to develop earthquake-resistant structures for public safety. Structures in many locations are required to consider designing more earthquake-resistant structures due to calculations made regarding the building structure’s ability to ensure the earth-quake’s vibration. Several medium-rise buildings in Bangkok have been required to improve their seismic performance to fulfill the new standard and to protect them from future earthquakes. Therefore, this study investigates the validation of updated design code and efficiency of retrofitting an existing shear wall medium-rise RC building that was planned with seismic concern but not in accordance with more modern code regulations using buckling restrained braces (BRBs). In addition, the possible locations of retrofitting BRBs are investigated. A typical 36-story RC shear wall residential building in Bangkok is used as the target building. An equivalent linear static analysis is performed to investigate the seismic performance of the target building. The results indicate that the seismic performance of the retrofitted building with BRB is improved when compared to the non-retrofitted building, and the retrofitted shear wall medium-rise RC building with the damper location close to the shear wall is the most efficient when compared to other locations.

Saingam, Panumas

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