Bamboo is a fast-growing biomass material with excellent performance, making it a preferred choice for the development of green and low-carbon building materials. However, challenges such as combustibility and difficulties in processing and utilization persist. In this study, bamboo chips are wrapped in fiberglass cloth and cemented with magnesium oxychloride cement (MOC) to develop green, environmentally friendly, flame-retardant, and carbon-storing bamboo-based composite panels. Firstly, the optimal ratio of the inorganic adhesive MOC was systematically investigated, and flue gas desulfurization gypsum (FG) was added to enhance its water resistance. The flexural strengths of the composite board in the direction of the bamboo fiber and that perpendicular to it were found to be 15.71 MPa and 34.64 MPa, respectively. Secondly, numerical simulations were conducted alongside plate experiments, analyzing the floor and wall made from the boards. The results indicate that since the fiber-reinforced bamboo board as a lightweight wall can meet the requirements for a two-story building, it does not satisfy safety standards as a floor slab due to the higher loads. Despite this limitation, the fiber-reinforced bamboo board shows promising application prospects as a green and low-carbon alternative.

Branching and free-form structures are widely used in large-span buildings. Their shapes are the main factors that affect their mechanical performances. Many studies have been carried out on the morphology of single structural systems, but less on hybrid structures. However, both of them often appear in the same building. In order to reflect the cooperative bearing of substructures in the optimization process of branch-supported free-form surface structures, this paper proposes a holistic shape optimization method. The proposed method extracts design variables based on the structural modeling process, and uses the coordinates in the parametric domain to realize a mathematical description of the positional relationship between substructures. Then, the sensitivity analysis method is used to adjust the position of design variables to reduce the overall strain energy, realizing the integrated shape optimization of this hybrid structure. The effectiveness of the method is validated through several numerical examples. The results show that the overall stiffness of the optimized structure has been significantly improved, and the process of integrated optimization is more convenient. Furthermore, the way of adjusting design variables directly affects the shape and mechanical performance of the optimized structure. This feature serves as a valuable design tool that can provide multiple feasible solutions for architectural and structural design.

The sensitivity method is a type of effective shape optimization method and the strain energy is a frequently used objective function. The change of a surface shape inevitably causes a change in its quality. However, the influence of the load term on strain energy sensitivity has not been considered in many studies. In order to make the influence clear, the formula of the strain energy sensitivity including the load term was first derived. Secondly, the influence of the sensitivity load term on the structural evolution was studied by using different optimization schemes. The results showed that the load term of strain energy sensitivity accounts for a small proportion of the whole strain energy sensitivity, but it still has a cumulative impact on the structural evolution, and the shell thickness has an impact on the role of the load term of the strain energy sensitivity. The load term could influence the rate of increase in the structural weight and had an impact on the shape change to some extent. Therefore, for general construction projects, the strain energy sensitivity should be with the load term if the shell thickness is very thin or a higher performance of the structure is required.

Utilizing phase change materials (PCMs) in passive energy-saving wall panels to regulate indoor temperatures during hot seasons can improve people’s thermal comfort and reduce the energy consumption of air conditioning systems. This study is based on the hot summer and warm winter climatic characteristics of Hainan. According to local meteorological data and residents’ living habits, a suitable phase change temperature of approximately 28 °C was determined. A composite PCM of paraffin and stearic acid n-butyl ester was prepared and tested for thermal performance. Encased in an aluminum box with non-penetrating aluminum rods to enhance heat transfer, the phase change panel was applied to the inner side of exterior walls. Thermal tests demonstrated that increasing the mass ratio of stearic acid n-butyl ester to paraffin lowers the melting point and latent heat. At a 3:7 mass ratio, the melting point of the composite PCM was 28.30 °C, and the latent heat was 128.26 J/g. The 20 mm thick panel maintained a stable phase change process, with unheated surface temperatures between 28 °C and 29 °C for up to 180 min. Compared to panels without aluminum rods, those with rods exhibited a 20% longer phase change time, extended heat transfer paths, and reduced liquid-phase convective heat transfer rates, demonstrating improved PCM utilization. Therefore, the phase change panel with non-penetrating aluminum rods exhibits excellent insulation and temperature control properties.

Free-form grid structures offer both aesthetic appeal and structural efficiency in long-span roof design and application, yet the potential of morphological design to optimize thermal performance has been long overlooked. This study proposes a multi-objective synergistic optimization framework which can improve the thermal environment and mechanical performance simultaneously for the roof. Focusing on public buildings in hot–humid climates, the research investigates the impact of roof geometry on indoor temperature under extreme thermal loading conditions and long-term thermal loading conditions. Furthermore, the evolution of thermal performance during mechanical performance-driven surface optimization is systematically analyzed. Subsequently, a dynamic proportional adjustment factor is introduced to explore the performance of the optimized results under different performance weights, with thermal and mechanical performance serving as the optimization objectives. Results demonstrate that thermal performance-driven optimization generates saddle-shaped free-form surfaces with alternating peak–valley configurations to achieve self-shadowing effects, reducing indoor temperature by approximately 2 °C but significantly compromising structural stiffness. Conversely, strain energy minimization yields moderate indoor temperature reductions, revealing a positive correlation between strain energy decrease and thermal performance improvement. In the multi-objective optimization considering thermal and mechanical properties, when the strain energy ratio is 0.5–0.7 (optimization balance zone), the indoor temperature decreases, while the structural stiffness and stability bearing capacity increase. This study provides a morphological–structural–environmental synergistic design reference for low-carbon long-span building roofs.

This study proposes a cross-disciplinary computational framework to advance the sustainable design of free-form grid roofs in hot climates, integrating architectural geometry with building thermal performance to enhance climate adaptability. Numerical analyses systematically explore the impact of thermal objectives, initial configurations, shape control strategies, and boundary constraints. The optimization results demonstrate that targeting indoor temperature under extreme heat yields saddle-shaped, self-shading morphologies, which achieve a measurable improvement in thermal comfort by reducing indoor temperatures by approximately 2 °C. A key practical finding is that symmetric-point control outperforms full-point control. While full-point control may generate forms with complex central depressions that complicate drainage, symmetric-point control consistently yields morphologies that are inherently more regular, symmetric, and constructible. This results in a superior balance among thermal performance, practical design attributes (e.g., drainage feasibility and construction simplicity), and geometric coherence—a combination that aligns closely with real-world engineering requirements. Furthermore, directional boundary constraints are proven to be effective tools for regulating passive shading performance. The proposed framework provides engineers and designers with a systematic and automated method for the climate-responsive and low-carbon design of free-form architectural morphologies, contributing to the development of more sustainable and resilient building infrastructure.