Roof Structure Research Articles

A comparative analysis of metaheuristic algorithms for optimizing curved roof structures

This article explores the optimal design of curved steel structures with a focus on minimizing their weight by determining the most suitable cross-sections. Customized optimization algorithms were developed to identify structural designs that meet safety and durability requirements, adhering to design constraints set by the ASD-AISC specification. To ensure reliable results, the study employs a variety of metaheuristic optimization methods: Biogeography-Based Optimization (BBO), Dynamic Harmony Search (DHS), Wolf Colony Algorithm (WCA), and Honey Badger Algorithm (HBA). The Honey Badger Algorithm, a relatively new addition to the field, was used for the first time in the context of structural optimization for curved roof systems. This unique approach aims to evaluate its performance in civil engineering problems and compare it with other established algorithms. The major challenges of this study lie in the inherent complexity of dome structures, which involve a large number of elements and nonlinear constraints. The subdivision of the structure into smaller groups was necessary to manage the computational load, although this introduced additional complexities. Despite these challenges, the metaheuristic methods demonstrated their robustness in addressing such intricate engineering problems. Additionally, data retrieval is facilitated through Open Application Interface (OAPI) functions, enabling seamless data transfer between SAP 2000 and Visual Basic. The study's final design example involves a dome model with 2556 elements, which was both modeled and optimized. The results demonstrate the effectiveness of these optimization algorithms in achieving structurally sound and efficient designs. The insights gained from this study contribute to our understanding of optimized cross-sections in curved steel structures, offering valuable guidance for improving structural performance and minimizing material usage.

Dynamic Wireless Sensor Network-Based Structural Health Monitoring System for Retractable Roof Structure

Retractable roof structure (RRS) works optimally under varying weather, but is prone to damage due to its complexity, requiring monitoring. Given RRS's large scale, wireless sensor networks (WSNs) are preferred, with dynamic WSNs better adapted to its motion than static ones. A tree-type network topology was designed for dynamic WSN, enabling fast self-routing. It is divided into subnets, each with a relay node as the parent and subordinate relay and sensor nodes as children. Network address reassignment method was proposed to sustain WSN communication during motion. This method involves operations of subnet affiliation change and relay node replacement, the former adjusts the hierarchy between relay nodes across different subnets while preserving parent-child relation within each subnet, and the latter swaps the roles of relay and sensor nodes within one subnet to form a new subnet. Basic communication module with processing, communication, and power management units was used to connect nodes. Dynamic WSN-based structural health monitoring (SHM) system with 372 sensors was developed for the Textile City Sports Centre Gymnasium. Mean errors between simulated and measured results were 10.4% for displacement, 13.6% for stress during construction, and 13.3% for tension during service, indicating good agreement. This suggests that the SHM system operated well in both phases. Maximal stress and displacement after unloading were 215.9 MPa and 549 mm, below allowable limits. Monitoring results revealed temperature field non-uniformity with a 9°C maximal difference, and strong temperature-stress correlation, with Pearson coefficients of 0.971, 0.973, and 0.955 for tie rod, chord, and web. RRS movement significantly impacted midspan tie rods in long main trusses, with a mean tension change exceeding 1000 kN. The research methods and conclusions offer valuable references for developing and applying RRS's SHM system.

Introduction to the Investigation of reproduction of the real geometry of UBM panels

The article concisely describes UBM technology (Ultimate Building Machine), that can be used as a solution for buildings and roof structures. The structure of this technology is made of double corrugated thin-walled steel profiles manufactured on the construction site by a self-contained UBM manufacturing factory on wheels. These panels serve as both the building envelope and the structural system. The specificity of the construction poses many design problems, especially the determination of the strength parameters and stiffness of the double-corrugated panels from which the structure is made. The article presents the results of spatial scanning tests of double-corrugated steel sheets, which were carried out using commonly available 3D scanning devices: Leica 3D Disto and MagiScan app. Additionally, results of numerical analyses performed on scanned samples and a comparison of these results with preliminary laboratory tests have been presented in the article. The purpose of scanning was to obtain an accurate and real geometry of the UBM panels, to implement it into a numerical software, and then to perform numerical analyses. Commonly available 3D scanning devices were used because using advanced 3D scanners is not popular nowadays for economic reasons, and hand-built geometric models pose a lot of problems and are not accurate enough. Promising results were obtained, which form the basis for further research.

A Calculating Method for the Height of Multi-Type Buildings Based on 3D Point Cloud

Building height is a critical variable in urban studies, and the automated acquisition of the precise building height is essential for intelligent construction, safety, and the sustainable development of cities. The building height is often approximated by the building’s highest point. However, the calculation method of the building height of the various roof types differs according to building codes, making it challenging to accurately calculate the height of buildings with complex roof structures or multiple upper appendages. Consequently, this paper utilizes point clouds to propose an automated method for calculating building heights conforming to design codes. The model considers roof types and allows for fast, automated, and highly accurate building height estimation. First, roofs are extracted from the point cloud by combining normal vector density clustering with a region-growing algorithm. Second, combined with variational Bayes, a Gaussian mixture model is employed to segment the roof surfaces. Finally, roofs are classified based on slope characteristics, achieving the automatic acquisition of building heights for various roof types over large areas. Experiments were conducted on Vaihingen and STPLS3D datasets. In the Vaihingen area, the maximum error, root-mean-square-error (RMSE), and mean absolute error (MAE) of the measured heights are 1.92 cm, 1.18 cm, and 1.13 cm, respectively. In the STPLS3D area, these values are 1.79 cm, 0.82 cm, and 0.68 cm, respectively. The results demonstrate that the proposed method is reliable and effective, which offers valuable data for the development, construction, and planning of three-dimensional (3D) cities.

Research on Deriving a Proportional System of a Roof Structure Through the Analysis of Hanok Architectural Design Methods

Hanoks are structures that have been built with unique techniques and styles since prehistoric times. Demand for hanoks is growing because they are recognized as climate-friendly buildings that make use of the natural environment as it is. However, there are a lack of standardized records concerning the methods or standards for constructing hanoks, so inferring them through the dimensional analysis of existing buildings is challenging. The roof of a hanok is its most beautiful part, and its proportions change the appearance of the hanok. Relying on existing examples or inherited figures when designing hanoks has led to the formation of uniform hanoks and the loss of their identity due to the lack of proportional standards. This study aimed to derive a proportional roof structure system by analyzing hanok architectural design methods. The employed method allowed for an analysis of the types of roofs and eaves of hanoks and extracted all the roof-related factors, such as the eave overhang, eave angle, roof angle, and hanok height. These data were compared with each other to find regularities and derive a final proportional system for a hanok roof structure. The analysis showed that the eave-height-to-roof-height ratio is 5.5:4.5, and notably, the sum of the eave and roof angles is in the range of 118°~120°, which means that the lower the eave angle, the higher the roof angle. Therefore, the roof structure of a hanok should not be designed based on a partial average value; rather, it should be based on a mutual proportional system considering the eave angle, roof angle, hanok height, and eave height. The results of this study can provide designers with a basis for creating hanoks through the use of the proportional system of roofs. This data basis guarantees continuity between the past and the present, and the proposed system can serve as a guide for hanok roof design and structural analysis.

Field evaluation of the efficacy of passive radiative cooling infrastructure: A case study in Phoenix Arizona

Radiative properties of shade structures affect their surface temperatures, sensible heat fluxes and longwave and shortwave radiation exchange. In fact, structures with high solar reflectance and thermal emittance have the potential to remain below ambient air temperatures, convecting sensible heat from the air to the surface and then radiating that heat to space—a sort of radiant heat pump.We explore cooling benefits of urban surfaces with high solar reflectance and high thermal emittance radiative cooling films through a field measurement campaign in Phoenix Arizona, USA. The tested films have solar reflectance and selective thermal emittance (in wavelengths 8–13 μm) close to 95 %. We applied films in both before-after and control-test experimental designs on thin metal roofs of park shade structures. We measured surface temperatures, surface heat fluxes, upward- and downward-welling longwave and shortwave radiation, and local weather conditions.Results demonstrate the ability of radiant cooling films to reduce surface temperatures on hot days below ambient air temperatures. Test surfaces with cooling films were an average of 7 °C cooler than control shelter surfaces over the diurnal cycle, reducing sensible heat fluxes into the environment by up to 80 %, and lowering mean radiant temperatures for pedestrians using the shelters by more than 3 °C. It was also observed that the sum of the net reflected shortwave and emitted longwave radiation over the diurnal cycle can exceed the total incident longwave and shortwave radiation on the surface, demonstrating the ability of these materials to radiatively “pump” heat out of the city.

Coal‐wall spalling prevention mechanism using advance‐grooving pressure relief in the large‐mining‐height working face of a shallow coal seam

AbstractIn mining, the roof structure of a working face with a large mining height in a shallow‐buried coal seam is prone to cutting instability in front of the support, which causes support crushing and coal‐wall spalling. This study analyzes 2201 working faces with large mining heights in the Haiwan No. 3 Mine by investigating the mechanical response law of coal walls under the transient excitation of roof structure instability. A mechanical model of coal walls under dynamic and static load coupling is established, revealing the formation mechanism of coal wall spalling and its main influencing factors. Prevention and control technologies of advanced grooving and pressure relief are proposed, and grooving parameters are determined. The results show that: During the mining process of large mining height working face in shallow buried coal seam, the step change of static response of coal wall is induced by the transient instability of roof structure, and the high abutment pressure is formed on the coal wall. At the same time, the strain energy and gravitational potential energy of roof cutting instability are released to form a dynamic load. Under the action of dynamic and static load, the plastic failure dissipation power of the coal wall is greater than the critical power, and the coal wall spalling occurs. The main influencing factors are mining load, mining height, and internal friction angle of the coal wall. The method of advanced grooving pressure relief can change the roof structure and coal force mechanism, by cutting off the connection between the coal wall and immediate roof, reducing the height of the coal wall force, effectively controlling the position of the roof cut off break line, reducing the static load effect of the roof on the coal, and transferring the position of the dynamic load response to the depth of the coal wall. When the grooving height‐depth ratio k is 0.75, the peak value of the abutment pressure moves 5.57 m to the front of the working face, and the pressure relief effect is the best. The above research results provide an effective active protection method for controlling coal wall spalling in fully mechanised working face with large mining height.

Investigation of Load Characteristics and Stress-Energy Evolution Laws of Gob-Side Roadways Under Thick and Hard Roofs

The stress environments of gob-side roadways (GSRs) are becoming increasingly complex during deep coal mining under thick and hard roofs. This leads to strong strata behaviors, including roadway floor heave, roof subsidence, and even coal bursts. Among them, coal bursts pose the greatest threat to production safety in coal mines. Coal bursts in a GSR strongly correlate with the load characteristics and stress-energy evolution laws of the roadway. This study analyzes the roof structures of double working faces (DWFs) during the initial weighting stage (IWS) and full mining stage (FMS) of gob-side working faces (GSWFs). This study also explores how varying roof structures affect the stability of GSRs. Three-dimensional roof structure models of DWFs and mechanical models of dynamic and static loads superposition on a GSR throughout the IWS and FMS of a GSWF were developed. An analysis identified the primary stress sources affecting the GSR throughout various mining stages of the GSWF. Subsequently, the principle of “three-load” superposition was developed. A novel method was proposed to quantify the stress state in the GSR surrounding rock across different mining stages of the GSWF. The method quantitatively characterizes the load of the GSR surrounding rock. Based on this, the criterion for judging the burst failure of the roadway was established. Numerical simulations are used to analyze the stress-energy evolution laws of the working face, coal pillar, and GSR surrounding rock during the mining process of the GSWF. These findings offer valuable references for studying and preventing coal bursts in GSRs under equivalent geological situations.

3D Building Modelling from ALS Point Clouds by Delaunay Triangulation and Graph Theories

Abstract. As an important task in 3D building reconstruction, 3D roof reconstruction attracts increasing attention. Existing methods have the issue of additional errors caused by multi-step processes, resulting in relatively high uncertainty and potentially affecting the reconstruction accuracy. Deep learning-based methods to achieve the direct extraction of roof vertices and edges for reconstructing 3D roof structures tackle the issue of additional errors while leading to another problem: the reliance on large labeled datasets for training. In this study, a fully rule-based method is proposed to achieve automatic 3D roof reconstruction. Roof vertices with their edges parallel to the x-y plane are first extracted from the point clouds, and subsequently, the left roof edges connecting vertices are inferred by using Delaunay triangulation. Finally, the 3D roof structure is reconstructed by using graph analysis based on the information of roof vertices and edges. This method simplifies the process of 3D roof reconstruction, and the experiment results demonstrate that the proposed method can effectively reconstruct 3D roof structures from point clouds.

Benefits derived from WASP (a Grasshopper plugin) to Design for Disassembly Principles in the Built Environment

Abstract Design for Disassembly (DfD, henceforth) is a way to improve the effectiveness of the disassembly process in built environments, and it mainly contains ten principles. Examples of the principles include deconstruction techniques; selected materials; reachable connections; utilizing connections with fewer bolts, screws, and nails; the straightforwardness of the structure and design; and versatility. On the other hand, the WASP plugin for Grasshopper (on Rhinocheros©) is a toolkit for discrete computational design to simulate the aggregation and assembly possibilities in the building system. This paper explores the integration of the WASP plugin within the context of DfD through three criteria: the aggregation processes of part geometries, connection locations, and their orientation toward the building elements. Design with discrete elements, which can be defined as shape grammars for building structure, is the primary approach for the joining behavior and detaching behavior of elements discussed in this paper. Also, this type of component-based design can optimize the geometry and data-driven generation of the structure. The design process in this way can be disassembly sequence planning and knowledge-based design by applying the design constraints. To illustrate the integration, research is conducted through WASP simulation in designing a traditional Iranian timber pavilion-inspired structure with a 3×3m footprint in a roof structure. The fusion of WASP and DfD represents a promising avenue for advancing circular design principles and achieving more sustainable, resource-efficient buildings. It is concluded from this study that WASP makes the aggregation simulation and assembly possibilities of the vertical and horizontal components in a building more accessible.

The mechanism and prevention of rockburst induced by the instability of the composite hard-roof coal structure and roof fractures

Despite the implementation of prevention and control measures, rockburst still occur. The characteristics of composite coal were analyzed by combining monitoring and early warning means. Two types of composite coal in the hard roof were distinguished based on their distinct initiation and destruction processes despite experiencing the same rockburst event. Rockburst caused by structural instability was studied in different mining stages, and the following conclusions were considered. 1) The mechanical model of the instability of composite coal in hard roof was established for different mining stages to reveal rockburst mechanisms. The high-speed advance of working faces changed the fractured structure of upper hard rocks in the pressure-relief protection range. The sudden fracture of long cantilever structures caused dynamic load disturbance to high-stress coal, which resulted in rockburst in the insufficient mining stage. The failure and deformation of coal under high-stress static loads created conditions for the instability and fractures of roof. The disturbance of low hard rock strata aggravated the deformations of damaged coal. Therefore, rockburst appeared in the full mining stage. 2) Structural instability and roof fracture caused by different factors were the main causes of rockburst for composite coal in hard roof in different mining stages. Relevant prevention and control measures were formulated to ensure the safety of working faces, which provided references for the prevention and control of rockburst in working faces under similar conditions.

Seismic performance of pentagonal type aluminum alloy suspen-dome structure with large opening

Prestressing technology is an effective way to enhance the mechanical properties of space structures. In view of this, a new pentagonal type aluminum alloy suspen-dome structure with large opening is proposed in this paper by introducing the lower cable support system into the aluminium alloy single-layer reticulated shell structure. The seismic performance of this new structure is investigated using time-procedure analysis. Firstly, the effects of rise-span ratio, thickness-span ratio, prestressing level, horizontal radius factor for lower chord nodes and roof loading on the free vibration characteristics of the structure with different supporting stiffness are investigated. The distributions of internal forces and displacements of members of overall structure considering lower support and roof structure only are analyzed. Subsequently, the dynamic response of the structure under seismic combinations of different dimensions and directions is investigated, and reasonable combinations that should be considered for simplified analyses are derived. Furthermore, seismic internal force coefficients are introduced to assess the degree of seismic effects on various types of members. On this basis, parametric analysis of the seismic performance of the structural performance is conducted and quantitative assessment of the sensitivity of the parameters is carried out. Additionally, the free vibration characteristics and dynamic performance of steel and aluminium suspen-dome are compared. The results show that considering the supporting structure weakens the structural stiffness while increasing the structural dynamic response; reasonable values of key parameters in the seismic design of the structure are obtained; and the rise-span ratio and thickness-span ratio are important influencing factors of the seismic performance of the structure. Besides, the internal forces of members in aluminium alloy suspen-dome are less affected by seismic effects than those in steel suspen-dome, and the new structure has good seismic performance.

APPLICATION OF BASIC PRINCIPLES OF BUILDINGS AND STRUCTURES PROTECTION IN THE CONDITIONS OF POSSIBLE SHELLINGS BY THE EXAMPLE OF REINFORCED CONCRETE LONG-SPAN TRUSS

For developing recommendations for the protection of buildings and structures under the threat of potential shelling, a summary and analysis of the scientific and technical work conducted by the SRIBP has been carried out, taking into account the principles and guidelines outlined in current regulations. The proposed recommendations can be used to develop national building codes and standards for the protection of building objects from potential shelling. Three groups of objects have been identified based on the risk of shelling, depending on the level of risk: highest risk (Group 1), increased risk (Group 2), and moderate risk (Group 3). The proposed approaches (with their advantages and disadvantages) for protecting construction objects from shelling include: direct calculation for shelling impacts, considering the most likely and unfavorable scenarios; application of direct structural requirements that will most likely ensure the overall survivability of the object or structure after being hit during shelling; general reserve of load-bearing capacity, usually by increasing reliability coefficients. Their application has been considered depending on the risk group and the responsibility classes of the construction object. For Group 1, a comprehensive set of all the mentioned measures is applied; for Group 2, mandatory minimum structural requirements; for Group 3, there are no specific requirements. As an example, a large-span roof structure of an industrial building from Group 1, which is subject to a damage scenario from a projectile impact, has been considered. During the summary of inspection and research results conducted by SRIBP, statistical data on types of large-span reinforced concrete roof structures of industrial buildings have been collected. It has been established that 24-meter-long reinforced concrete trusses are significantly widespread, and they have been selected for consideration as an example of applying the proposed protection approaches. Based on the summary of inspection results, a damage scenario for the truss has been defined, which involves the complete or partial loss of one of the elements (diagonal and vertical web members) due to a projectile impact on the roof structure. Approaches to developing protection for load-bearing structures, adapted for the 24-meter reinforced concrete truss in question, which has sustained element loss after impact, are presented.

Acoustic optimization design for the laying schemes on the composite roof structure of high-speed train

ABSTRACT If the weak sound insulation in the roof during high-speed train travel through tunnels can be addressed by adjusting the order of materials, this will meet design requirements for both economy and lightweight construction. This paper studies this problem. First, a prediction model for sound transmission loss (STL) of the roof was established to investigate the impact of different material placement schemes and optimize their arrangement. Then, the optimal placement schemes between the roof and floor were compared using STL tests. Finally, this study also examined how an optimal scheme mitigates power radiation from the roof into the train interior under typical mechanical excitations. The results indicate that the optimal laying scheme for the roof differs from that of the floor. By placing sound absorption materials on the inner side of aluminium extrusion and sound insulation materials on decorative plate, it effectively enhances vibro-acoustic characteristics of the roof.

Simplified Procedure for the Design and Optimisation of Oval Tensile Spoke Wheels for Roof Structures

This paper presents a simplified procedure for the design and shape optimisation of oval tensile spoke wheels to be used in roof structures for grandstands in sports stadiums. This procedure combines graphical methods with simple numerical methods to obtain the geometrical definition of an oval wheel and to estimate the prestressing forces. It also allows for the compression forces in the outer ring to be estimated and compared with those in a circular wheel. This makes it easy to make small geometrical adjustments for optimisation. Application examples are given for each step of the procedure. Several wheel designs are defined, showing how the shape of the inscribing oval determines the magnitude of the forces in the outer ring.

Study on overburden rock structure characteristics and surrounding rock control technology of island working face

Based on the background of ZF2822 island working face in Xiagou Coal Mine, the characteristics of overburden fracture structure and surrounding rock control technology of island working face are explored by means of theoretical analysis, numerical simulation and field measurement. The results show that the ten morphological structures of the main roof fracture can be divided into four typical symmetrical structures and six asymmetric structures. According to the stress calculation formula of the key block B to the coal pillar, the stress characteristics of the 10 structures are classified and the risk classification is carried out. Four typical structures (a), (b), (c) and (d) were constructed to simulate the stress and strain characteristics of surrounding rock. The overlying strata subsidence displacement values of (a), (b), (c) and (d) at the roadway are 1.75 m, 1.5 m, 0.8 m and 0.6 m respectively, and the maximum stresses are 26.6 MPa, 19.5 MPa, 15.5 MPa and 10.0 MPa respectively, (a) > (b) > (c) > (d). Therefore, the surrounding rock control technology of gob-side roadway in island working face is put forward, the fracture structure of basic roof is determined and the reasonable applicable type of gob-side roadway is selected. The results after pressure relief show that the average daily microseismic energy of ZF2822 working face after pressure relief is 0.87 × 104 J, which is about 42.38% lower than that of April. The average stress is 1.13 MPa lower than that of the mining before the pressure relief area, and the decrease is 22.42%. It shows that the pressure relief has played a very good effect and provides a reference for the same type of mine.

Design of a Six-Story Teaching Building: A Comprehensive Approach to Safety and Structural Efficiency

This paper describes teaching building design. The project, designed for the teaching building, prioritizes safety in its main structure, a reinforced concrete frame with six floors above ground. The story heights are 4.2m, 3.9m, 3.9m, 3.9m, 3.9m and 3.9m, respectively, and the building's total height is 27.6m. The construction site category is classified as type II, and the first group's seismic fortification intensity is 7 degrees. The process includes architectural design, structural design, and PKPM checking calculation. Architectural design mainly consists of a general description. The plan, elevation, section, and draft of the corresponding building are drawn according to the relevant information and requirements provided by the design task book. Structural design mainly includes load statistics, calculation of internal force and displacement of the frame, a combination of internal force, and calculation of staircase, slab roof, floor slab and frame structure. The calculation of displacement, internal force, and reinforcement of the whole frame structure is carried. Out using PKPM. In the course of architectural design, safety is a paramount consideration, in line with the principles of safety, applicability, beauty, economy, and energy-saving requirements, referring to national standards and relevant materials, and strictly following the requirements of relevant architectural design standards, the design of each link is not only a comprehensive scientific consideration of its own but also a related discussion with teachers, as detailed in the construction plan. The frame structure is adopted,in this structural type. It mainly includes structure layout and calculation sketch determination, load calculation, internal force calculation, internal force combination, main beam section design, and reinforcement calculation, frame column section design and reinforcement calculation, secondary beam section design and reinforcement calculation, floor and roof design, staircase design etc. Among them, the D-value method is used to calculate the internal force of the structure under horizontal load, and the distribution method is used to calculate the internal force of the structure under vertical load (dead load and live load).

Determining patterns of the vertical load on a covered wagon roof with a frame in the form of a triangular arch

The object of this paper is the processes of perception and redistribution of loads in the roof of a railroad covered wagon with a frame in the form of a triangular arch. To reduce the tare of the covered wagon, it is proposed to improve the structure of its roof. A feature of this improvement is that the roof frame is made in the form of a triangular arch with a reinforcing belt. This contributes to the reduction of the total mass of the roof compared to a typical structure. The selection of execution profiles of the beams forming the arch is carried out according to the maximum values of the moments that act in their cross-section. Taking into account the chosen profile of the arches, the calculation of the strength of the roof when it receives vertical loads was carried out. It was established that the strength of the roof under the considered load schemes is within the permissible stress values. Since the improvement of the roof structure contributes to the reduction of its weight by 1.8 % compared to the prototype, the movement of the covered wagon was evaluated under conditions of moving while empty. To this end, a mathematical modeling of the load of the covered wagon in the vertical plane during its movement along the joint unevenness was carried out. On the basis of the performed calculation, it was established that the movement of the wagon is assessed as "good". Special feature of the results is that the reduction of the tare of the supporting structure of the wagon was achieved by improving its roof, as the least loaded unit. The field of practical application of the results is railroad transport, including other areas of mechanical engineering. The conditions for the practical use of the results are a symmetrical roof load scheme in operation. The results of this research could contribute to advancements related to the design of modern structures of freight wagons with improved technical and economic indicators

Design Analysis and Analysis of Roof Structure Work in the Implementation of the Exit Gate and Cafeteria Construction Project at Delta Surya Sidoarjo Hospital

Building design and planning requires a very high level of precision and a relatively long time. Therefore, most consultants and construction implementers (contractors) rely on technical application support during project planning, design, and construction report preparation. A very commonly used application in Indonesia is AutoCAD. Supported with other applications such as SAP2000 and ETABS to create 2D and 3D images and analyze the strength of structures. The definition of design methods is the ways in which a designer creates an object. Some of the design methods that are often used are as follows: a. Explosing, which is a design method by seeking inspiration through critical thinking to produce a design that has never been created. b. Redefining, which is a design method by reprocessing a design to become something different and better. c. Managing, which is a design method by creating designs in a sustainable and continuous manner. d. Phototyping, which is a design method by improving and/or modifying the design of the ancestral heritage. e. Trendspotting, which is a design method by creating a design based on a developing trend. In the implementation process, the contractor PT Muliif Teknika Utama requires technical drawings that are used for work references. Where later the field results will be in accordance with the planning time. In the process of work on the structure of the field team, the implementation team needs shop drawings as a reference for implementation. Here is an example of a working drawing of a roof plan. Based on the results of the observations that have been made, the design needed in the work of the roof of the exit gate and cafeteria in the hospital. Delta Surya Sidoarjo includes: a. Drawing of the roof truss plan b. Drawing of the roof component plan in the form of placing curtains, rafters, battens, and breising column c. Cut drawings d. Detail drawings.

Safety and high-recovery mechanisms and application research for initial mining of thick-coal-seam with complex structure and thick-hard roof

Thick-coal-seam with complex structures and thick-hard roof in the initial mining phase pose various challenges, including a long weighting interval, strong rock pressure, poor top coal caving performance (TCCP), and significant coal loss. These problems directly affect the safety and efficiency of the mining operations. This study employs the principles of elastic thin plates and ellipsoidal bodies to unravel the formation mechanism of strong rock pressure in thick-hard roof and the influence of parting on the TCCP. In addition, a hydraulic fracturing technique is proposed for safe-efficient recovery during the initial mining phase. The reliability of this technique is verified through numerical simulations and field experiments. The research findings reveal the following. (1) The primary causes of strong rock pressure in the mining face are attributed to a long weighting interval and wide collapse range of the main roof, and the weighting interval is primarily influenced by the thickness and tensile strength of the main roof. (2)The key factor affecting the TCCP is the cantilever beam structure formed by the fracture of the thick-hard parting, as it intersects the ellipsoidal body during coal caving. The simultaneous fracturing of both the top coal and roof can reduce the weighting interval on the working face. This process effectively decreased the strength of the thick-hard parting within the top coal, while simultaneously enhancing its load strength and eliminating the cantilever structure resulting from the parting fracture. It not only reduces the first weighting intensity but also promotes the early and proper coal release, thereby enhancing the TCCP and ensuring safe-efficient mining during the initial mining phase. (3) Aiming at the difference in the strengths of the top coal and roof, a graded hydraulic fracturing technique and system were proposed. Fracturing boreholes with a diameter of 60 mm, spacing of 10 m, and height of 20.85 m, which can economically and effectively ensure the fracturing results. Field applications have demonstrated that fractured coal and rocks in fracturing areas exhibit well-developed fractures. During the initial mining phase, the weighting interval in the working face was reduced by 20 m, resulting in a decrease in the overburden pressure and 26.9% reduction in the lumpiness of the top coal. Additionally, the recovery rate increased by 31.19%.