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In this study, seismic fragility analysis of multi-span steel truss bridges still giving service in railway network of Turkey was aimed. For this purpose, two representative multi-span steel truss bridges were selected in Turkish railway lines. A detailed three-dimensional inelastic finite element (FE) model for each bridge was created using commercial FE software. These models were used to perform non-linear time history analyses for each of the selected 30 ground motions scaled to 10 different peak ground acceleration (PGA) values to assess seismic demands of the bridges. To develop fragility curves, probabilistic seismic demand models (PSDMs) were defined. The most appropriate ground motion intensity measure (IM) for PSDMs of both bridges was determined among 11 IMs and the PGA was found as the optimal IM. Finally, the fragility curves for both the components and structural systems of the bridges were developed. The results clearly showed that the multi-span continuous (MSC) steel truss bridge is more vulnerable than the multi-span simply supported (MSSS) steel truss bridge, and for both bridge types, steel bearings are the most vulnerable components. Additionally, top wind braces for the MSC bridge as well as transverse beams and truss vertical members for the MSSS bridge were found as the most vulnerable superstructure members.

The article is devoted to the calculated regulation of the stress deformation state (SDS) of combined steel trusses, which allows to reduce the efforts in some sections of the structure by increasing the efforts in other and design evenly stressed structures as the most rational systems. It is shown that the calculated method of SDS regulation makes it possible to reduce steel consumption by up to 34%. Four methods of calculated SDS regulation are proposed. The advantages of combined structures are given: the concentration of materials and the possibility of designing them as low-element. As shown in the example, for the quantitative criterion of quality it is possible to use rationally the maximum potential energy of deformation. Dependences for calculation of the maximum potential energy of compressed stretched, and compressed-bent elements of rod-bearing steel structures are given.

Cold-formed stainless steel is becoming popular as a structural member with its increased corrosion resistance and durability when compared with carbon steel. Examples of cold-formed steel structures include trusses, wall frames and portal frames. In cases where increased axial strength is required, it is becoming increasingly popular to use battened built-up channel sections, instead of just back-to-back channel sections. For carbon steel battened built-up columns, limited experimental and finite element (FE) results are available in the literature. These results, however, are not applicable to cold-formed stainless steel. This issue is addressed numerically herein. Using the finite element model (FEM) previously reported by the first author of this paper for cold-formed carbon steel, an extensive parametric study, comprising 132 models is described in this paper for stainless steel battened built-up columns. Two different grades of stainless steel, that is, austenitic EN1.4404 and ferritic EN1.4003 have been considered. The effects of slenderness, different cross-sectional geometries and batten depth are investigated. From the results of parametric study, it was found that most of the short, intermediate, and long columns failed by distortional-flexural buckling interaction. For stub columns, distortional buckling governed the failure mode. The axial strengths determined from the parametric study were then compared against the design strengths calculated by the design guidance of carbon steel built-up columns from the American Iron and Steel Institute (AISI (2016)) and Australian and New Zealand Standards (AS/NZS (2018)). This is due to the unavailability of design guidelines for stainless steel battened built-up columns. From the comparison, it was found that the design strengths are 4% conservative on average for stainless steel battened built-up columns. Therefore, a design recommendation is proposed to modify the current design rules of carbon steel built-up columns, which was found to be accurate for stainless steel battened built-up columns.

Tessellating a periodic unit cell of lattice material to fill a design space in complex geometries has many challenges arising from their computer-aided design (CAD) modeling intricacy. A solution to this difficulty is the use of trimmed micro-truss lattice structures with a conformal net. This paper presents a novel algorithm for constructing conformal lattice net as wireframe of one-dimensional line segments suitable for Bravais cubic symmetric truss-based topologies. The novel algorithm is an excellent candidate when dealing with lattice structures using cubic, body-centered cubic (BCC), face-centered cubic (FCC), and/or diamond unit cell configurations. The wireframe structure is easily transferred into one-dimensional beam elements for microscale optimizations to obtain a functionally graded lattice material. It is shown that introduction of the lattice net resulted in a significant reduction in the mass of the optimized design.

With the development of China's construction field, prefabricated building structure has gradually become a very common building structure in the current construction engineering by virtue of its many advantages in the actual construction field. Combined with the engineering practice, this paper summarizes the hoisting technology of precast composite slab and precast staircase in prefabricated building structure. This paper focuses on the optimization design of laminated plate support under the conditions of wood formwork and aluminum formwork system and the key and difficult points in the construction process, and puts forward a set of practical and feasible construction methods for prefabricated components. This paper focuses on the analysis of the design concept, materials, structural form, manufacturing technology, hoisting and installation, and construction technology of M-type light steel concrete composite slab. This paper discusses and summarizes the advantages and disadvantages of M-type light steel reinforced concrete composite slab at present, and analyzes its development and application prospects. At the same time, in order to determine the reasonable type of laminated plate, the material budget analysis of assembled laminated plates with different structural forms is carried out. The conclusions are as follows: PK prestressed concrete composite slab has great advantages in the whole material budget cost, which is suitable for all kinds of span buildings. One way steel truss slab and YH prestressed concrete composite slab are suitable for small span buildings.

In the Ankeng Light Rail MRT system (ALRMS) project, the U7 box girder passes crossing the Erbads creek and needs a temporary supporting system for the construction work. In this study, three temporary shoring system options were proposed to be the construction method. The D-B Contractor, New Asia construction and Development Corporation, evaluated and selected the optimal choice, The Steel truss frame with supporting beams, to serve as the temporary supporting system. Compare the deflection of Δmax and Δactual, which are 1.609 cm and 1.59 cm, respectively. This result presented that the shoring system composed of the H912*302*18*37 supporting beams and steel truss frame had achieved outstanding performance and work to construct the U7 box girder. This paper presents how the three options are evaluated and the detailed construction processes along with the survey verification for the method.

The aim of the work - to propose a scheme and analytical calculation of a statically definable planar truss with a suspended lower belt. Methods. The formula for the dependence of the deflection of the truss under the action of a uniform load on the lower belt on its size and the number of panels is derived in the computer mathematics system Maple. The forces in the rods are found from the solution of the general system of equilibrium equations of all nodes in symbolic form. The deflection is calculated using the Maxwell - Mohr's formula. Generalization of a number of formulas for deflection obtained by increasing the number of panels sequentially to an arbitrary number is performed by double induction using two independent parameters. In this case, special operators of the Maple system are used, allowing for a sequence of coefficients in the desired formula to create and solve recurrent equations that satisfy the elements of the sequences. Results. The obtained solutions have a polynomial form for the number of panels. Curves of deflection dependence on the number of panels are constructed and analyzed. Asymptotic properties of solutions are found in the case of a fixed span length of the structure and a given total load. The proposed scheme is a statically determinate structure with two independent parameters of regularity allows for the finding of a fairly simple analytical solution. The resulting formula is most effective in calculating systems with a large number of elements, where numerical methods tend to accumulate rounding errors.

The aim of the work is to derive a formula for the dependence of the first frequency of the natural oscillations of a planar statically determinate beam truss with parallel belts on the number of panels, sizes and masses concentrated in the nodes of the lower truss belt. Truss has a triangular lattice with vertical racks. The solution uses Maple computer math system operators. Methods. The basis for the upper estimate of the desired oscillation frequency of a regular truss is the energy method. As a form of deflection of the truss taken deflection from the action of a uniformly distributed load. Only vertical mass movements are assumed. The amplitude values of the deflection of the truss is calculated by the Maxwell - Mohrs formula. The forces in the rods are determined in symbolic form by the method of cutting nodes. The dependence of the solution on the number of panels is obtained by an inductive generalization of a series of solutions for trusses with a successively increasing number of panels. For sequences of coefficients of the desired formula, fourth-order homogeneous linear recurrence equations are compiled and solved. Results. The solution is compared with the numerical one, obtained from the analysis of the entire spectrum of natural frequencies of oscillations of the mass system located at the nodes of the truss. The frequency equation is compiled and solved using Eigenvalue search operators in the Maple system. It is shown that the obtained analytical estimate differs from the numerical solution by a fraction of a percent. Moreover, with an increase in the number of panels, the error of the energy method decreases monotonically. A simpler lower bound for the oscillation frequency according to the Dunkerley method is presented. The accuracy of the lower estimate is much lower than the upper estimate, depending on the size and number of panels.

This paper describes the rehabilitation procedure of the roof timber structure of a multiuse pavilion in Viseu, Portugal. The roof structure consists of a series of parallel double timber trusses, partially concealed above a polyhedral wooden plank-made ceiling. Recently, the support of one of the trusses failed and another one has been assessed as in a pre-failure condition. Some load-redistribution and the prompt shore of the structure prevented the generalized collapse. The subsequent inspection and assessment led to the conclusion that the primary cause of the collapse was the failure perpendicular to the grain of the solid timber elements inserted between the double rafters and tie-beams. The replacement of the existing with a steel structure, and the repair and reinforcement of the existing wooden trusses, were considered as intervention possibilities. The latter revealed much cheaper, less time-consuming and in line with the international recommendations on rehabilitation works, and was therefore adopted. An innovative solution, consisting of the replacement of the central timber elements in all the supports, resulted in minimum visual impact and improved the load bearing capability beyond its original value. Doi: 10.28991/cej-2020-03091628 Full Text: PDF

Ambitious mission mode project ‘Affordable Housing for All’ proposed by the Government of India requires an innovative technology for speedy construction of cost-effective residential housing systems. Precast concrete sandwich panels with reinforced concrete wythes, expanded polystyrene core and truss shear connectors can be considered as a suitable alternative to conventional brick masonry walls and reinforced concrete floors. In this paper, a typical plan for mass housing systems is arrived and concrete sandwich panels are proposed to be used in the mass housing systems. In the proposed housing plan, the dimension of each room was selected based on length and width of the concrete sandwich panels (achieving dimensional co-ordination). The design strength of concrete sandwich panels is obtained from the experimental studies available in the literature and compared with actual loading effects on the mass housing system with the proposed plan. The study shows that concrete sandwich panels can be used for acting as load bearing walls and floors in housing systems. The study also indicates that dead weight of the housing systems could be reduced significantly by using concrete sandwich panels. Further experimental and analytical studies are required for assessing the structural behavior of the housing systems with concrete sandwich panels under lateral loads.

The paper presents the results of a study of the possibilities of a new technology aimed at production of truss cores for sandwich panels. This technology is based on the combination of folding technology, tailored fiber placement, and transfer molding.

A space truss structural system is a three-dimensional arrangement of linear elements in a pyramid pattern forming a Double Layer Grid (DLG) system. Space trusses are an elegant and economical means of covering larger areas such as roof systems, in a wide variety of applications such as a stadium, aircraft-hanger, assembly hall, etc. The major problem encountered in using the space truss as a roofing system is the sudden failure of the whole structure due to critical buckling of the top chord member. Earlier research has shown that the optimal solution to overcome such a failure is by providing a small thickness of concrete slab over the space truss, so that the space truss with concrete slab (Composite Space Truss) will act as a floor system for the multi-storey building. For better ventilation and lighting in the building, the need for openings in the composite space truss is unavoidable; however, providing an opening in the concrete slab will reduce the load carrying capacity of the structure. The analysis of a composite space truss of size 30m x 30m with all possible locations of openings for four different support conditions was carried out using ANSYS in order to study the load - deflection behaviour. Further, the ductility factor and energy absorption capacity of the composite space truss with different locations of slab openings were compared.

Strategic dentin preservation is the prime objective of this case report (i.e. leaving a truss of dentin between the 2 cavities thus prepared). Permanent teeth with an indication for endodontic treatment can be treated via the truss access cavity design rather than traditional access cavity protocol using copious irrigation. The teeth were then given post-endodontic restorations. Endodontically treated teeth did not show any post-operative symptoms or any presence of post-operative periapical radiolucency or flare-up. The main objective of Orifice oriented access/truss access approach mainly stresses on the preservation of the healthy tooth structure with the minimally invasive approach. This minimal invasive approach in truss access designs avoids the need for conventionally placed crowns. Thus, the aim of this case report was to strategically plan truss access cavity designs on premolars.

Historical masonry stone mosques with timber truss roofs were widely constructed all over the world. Due to the complex structural behaviors of this type of building, it is difficult to determine natural frequencies during the seismic safety evaluations numerically. The article aims to develop simplified natural frequency formulas based on ambient vibrations for the historical masonry stone mosques with timber truss roofs. Fourteen masonry stone mosques with timber truss roofs built in the Eastern Black Sea Region of Turkey are selected for the study. Experimental natural frequencies, mode shapes and damping ratios of the selected mosques under ambient vibrations are determined using the Operational Modal Analyses. Ambient vibration-based simplified natural frequency formulas based on the geometrical dimensions for the masonry stone mosques with timber truss roofs are obtained by using the statistical regression analysis. The proposed formulas for the first three frequencies are verified with the control data.

The aim of this paper is to investigate the nonlinear behavior of space truss roofs subject to different load accumulation forms considering the effect of initial imperfection and slenderness ratio of the truss members. For this, a typical space truss roof using MERO-connection type with flat double-layer was selected as a sample. 3D model of the roof was developed and analyzed by using OpenSEES. Nonlinear behavior of each typical bar of the space truss roof, which, was mainly composed of particular sub-elements such as a tubular element, bolts, sleeves and spheres was represented by a single truss bar. Axial load-displacement relationship of each single truss bar was obtained from nonlinear analysis performed under reversal cyclic loading. Besides, three different types of load distribution that simulates accumulation of rainwater or drifted snow were taken into account as an external load acting on upper layer of the roof system. Analyses results showed that load carrying capacity of the space truss roofs was susceptible to the form of accumulation and reduces abnormally when the accumulation, in particular, occurred locally. Furthermore, failure mode of the system designed with optimal solution was dominated by buckled truss bars and brittle failure occurred. Also initial imperfection had a negative effect on the members in compression., Bu çalışmada uzay kafes çatı sistemlerinin çeşitli yük birikme senaryoları altındaki doğrusal olmayan davranışı, çubuk eleman başlangıç kusurları ve çubuk eleman narinlikleri de dikkate alınarak incelenmiştir. MERO düğüm noktasına sahip iki adet örnek uzay kafes çatı sistemi OpenSEES yazılımı üç boyutlu olarak modellenerek analizler gerçekleştirilmiştir. Bulonlar, somunlar ve düğüm noktası kürelerinden oluşan her bir çubuk elemanın davranışı tekil çubuklar üzerinde tanımlanarak genel sisteme aktarılmıştır. Her bir çubuk elemanın eksenel yük-yerdeğiştirme davranışları çevrimsel tekrarlı yükler altında analizler gerçekleştirilerek elde edilmiştir. Genel sistem analizleri çatının tamamında, yarısında ve dörtte birinde yağmur suyu veya kar yükü yığılmalarını yansıtacak şekilde belirlenen yükleme altında gerçekleştirilmiştir. Analizler sonucunda uzay kafes çatı sistemlerinin yük yığılmalarına karşı hassas oldukları ve lokal bölgelerde oluşan yük yığılmalarının sistemin taşıma kapasitesini düşürdüğü görülmüştür. Bunun yanında, en ekonomik kesitlerle boyutlandırılan sistemde göçme basınç çubuklarının burkulması ile gevrek bir şekilde meydana gelmiştir. Ayrıca, çalışma kapsamında başlangıç kusurlarının çubuk elemanların basınç kapasitelerini düşürdüğü görülmüştür.

The west flyover at Stockley airport junction forms part of the ‘On network works’ of the Crossrail project. The structure is a two-span weathering steel truss 117·8 m long, curved in plan, carrying one new line from Heathrow airport to London. It passes at a highly skewed angle over five railway tracks, including the Great Western main and relief lines. The structure was launched into position at Easter 2014 and was opened to regular services at the end of December 2014. The west flyover includes the longest single span constructed on the Great Western railway since Brunel's Saltash Bridge in 1859. The trusses are formed from fabricated closed box sections. The structure was assembled on a strengthened earthworks approach ramp using extensive site welding. The launch philosophy was based on a requirement to install the superstructure while maintaining unrestricted live railway operations beneath. The launch system included roller bogies on the approach ramp with jackable, sliding stainless steel–polytetrafluorethylene (PTFE) supports at the abutments and central pier. To facilitate construction of the central pier crosshead within a restricted island site between the up main and down relief lines, a permanent, bespoke, precast concrete formwork shell was developed.

Introduction. By method of induction using three independent parameters (numbers of panels) formulas for deflection under different types of loading are derived. Curves based on the derived formulas are analyzed, and the asymptotic of solutions for the number of panels are sought. The frame is statically definable, symmetrical, with descending braces. The problem of deflection under the action of a load evenly distributed over the nodes of the upper chord, a concentrated load in the middle of the span, and the problem of shifting the mobile support is considered. Materials and methods. The calculation of forces in the truss bars is performed in symbolic form using the method of cutting nodes and operators of the Maple computer mathematics system. The deflection is determined by the Maxwell – Mohr formula. Operators of the Maple computer mathematics system are used for composing and solving homogeneous linear recurrent equations that satisfy sequences of coefficients of the required dependencies. The stiffness of all truss bars is assumed to be the same. Results. All the obtained dependencies have a polynomial form for the number of panels. To illustrate the obtained solutions and their qualitative analysis, curves of the deflection dependence on the number of panels are constructed. Conclusions. A scheme of a statically definable three-parameter truss is proposed that allows an analytical solution of the problem of deflection and displacement of the support. The obtained dependences can be used in engineering practice in problems of structural rigidity optimization and for evaluating the accuracy of numerical solutions.

Ji'nan Huanghe rail-cum-road bridge is a continuous steel truss girder bridge with rigid suspension stiffening chords. Considering the structural characteristics and construction conditions of the ...

In the highways of mountainous areas, the erection of the large-span reinforced concrete box-type arch bridges using the cantilever casting method has unique advantages due to its adaptability to those environments. However, what prevents engineers from choosing this design in practice is that, the efficiency, cost, and safety problems resulting from the defects of the temporary facilities, which are due to the span increase, may immediately make the scheme less attractive. To fully consider the merits of this bridge type, new techniques of the temporary facilities are developed. A new form traveler based on the feathers of such arch rings is invented to promote erection efficacy; this new form further facilitates the technical upgrades of the buckle-anchor system monitoring-control and temporary prestressing design, which together eliminate the difficulties brought by the span increase. The inverted-type triangle traveler composed of tiled main truss structures, with the walking hook and anchor tie rod detached, is used to achieve space adaptability, light weight and modularization. The semiautomatic deviation-rectifying system, which combines the technologies of real-time data collection of the buckle pylon deviations and automatic synchronized tensioning, is developed to ensure the safety of the buckle-anchor system. The temporary short prestressed tendons are designed for control of the arch ring tensile stresses. The effectiveness of the technical upgrades has been demonstrated in the construction application of the Shatuo Bridge in Guizhou, China, which provides a promising alternative for the construction of large-span box-type arch rings of concrete arch bridges with a low cost, high efficiency, and high safety assurance.

A beam statically determinate truss with an arbitrary number of panels, in one of the nodes of which there is a massive load, is considered. The mass of the rods of the truss is neglected. A formula is derived for the dependence of the vibration frequency of the load on the hinge number in which it is located. The rigidity of the truss in the frequency equation is determined by the Maxwell-Mohr's formula. Forces in rods are determined in symbolic form by cutting out nodes in a program written in the computer mathematics system Maple. By a method of double induction (by the number of the node where the load is located and the number of panels), a series of particular solutions is generalized to an arbitrary case. A recurrence equation that is satisfied by a sequence of coefficients of particular solutions is given by a special operator of the Maple system.

In truss structural optimization the most frequently optimized factor of a structure is its weight. The minimization of weight contributes not only to savings in material, but also in other aspects of the structure such as number of elements used, number of welds needed, outer surface area, etc. This research aims to show the difference in optimal solutions for four different topological cases of a typical trapezoidal roof truss looking at their effects on overall outer surface area. The truss layouts are optimized for sizing, and a combination of sizing and shape with a minimal weight objective function. In order to ensure the most practically applicable solutions the example optimized in this paper uses dynamic constraints for buckling, stress constraints, and nodal displacement constraints. The overall outer surface area for all cases is compared, as surface protection accounts for a substantial part of the total cost of roof truss construction. Optimal solutions show a lack of correlation between weight and surface area, which is discussed in the conclusion.

Inspired by crystallography, the periodic assembly of trusses into architected materials has enjoyed popularity for more than a decade and produced countless cellular structures with beneficial mechanical properties. Despite the successful and steady enrichment of the truss design space, the inverse design has remained a challenge: While predicting effective truss properties is now commonplace, efficiently identifying architectures that have homogeneous or spatially varying target properties has remained a roadblock to applications from lightweight structures to biomimetic implants. To overcome this gap, we propose a deep-learning framework, which combines neural networks with enforced physical constraints, to predict truss architectures with fully tailored anisotropic stiffness. Trained on millions of unit cells, it covers an enormous design space of topologically distinct truss lattices and accurately identifies architectures matching previously unseen stiffness responses. We demonstrate the application to patient-specific bone implants matching clinical stiffness data, and we discuss the extension to spatially graded cellular structures with locally optimal properties., Proceedings of the National Academy of Sciences of the United States of America, 119 (1), ISSN:0027-8424, ISSN:1091-6490

The main causes of damage to wooden structures in historic buildings are the effects of weather conditions and related aging processes. In the case of the roof truss of a 16th-century church in Lubów, the technical condition is additionally affected by leaking roof covering, damaged gutters, downpipes and flashings. Some elements of the wooden structure underwent biological corrosion, which lost its strength values. The roof truss of a 16th-century church in Lubów comes from the period of construction of the building. Due to the historic values of the structure of the truss, the renovation works do not intervene when the works would change its form, shape and type. The truss renovation is based on the assumption of maintaining original construction solutions, location of elements and cross-sections.

Bu çalışma, boru ve kutu profillerden oluşmuş kafes sistem T-birleşimlerinin eksenel yük altında yangın sonrası davranışlarını sonlu elemanlar yöntemi kullanarak incelemeyi amaçlamaktadır. Bunu için farklı geometrik özelliklere sahip T-birleşimler sonlu elemanlar programı kullanılarak modellenildi. Öncelikle ısı transfer analizi yapılarak, oluşturulan sayısal modeller ISO 834 yangın eğrisine bağlı olarak ısıtıldı ve sonra soğutuldu. Yangın sonrası artık gerilmelere ve deformasyonlara maruz kalmış birleşimlere, maksimum dayanıma ulaşıncaya kadar örgü elemanı ucundan eksenel yük uygulanıldı. Tüm birleşimlerde göçme sınır durumu başlık elemanı cidarında plastikleşme olarak tespit edildi. Yangın öncesi ve sonrası birleşimlerin dayanımları karşılaştırıldı. Sayısal sonuçlardan elde edilinen bilgilere göre yangın sonrası tübüler T-birleşimlerin dayanımları %23,5 ’a kadar düşmektedir. Ayrıca, birleşimler üzerindeki sıcaklık dağılımları, örgü-başlık eleman oranlarına ve başlık elemanının et kalınlıklarına bağlı olarak değişmektedir. Yangın sonrasında oluşan artık gerilme ve deformasyonlar boru ve kutu T-birleşimlerin dayanımlarına önemli derecede etki etmektedir., This study aims to investigate the post-fire behavior of truss system T-joints made of pipe or box profiles under axial load using the finite element method. Hence, T-joints with different geometrical properties were modeled using the finite element program. First of all, heat transfer analysis was performed and the numerical models were heated based on the ISO 834 fire curve and then the joints were cooled. An axial load was applied from the end of the brace member to the joints, which were exposed to residual stresses and deformations after the fire, until they reached the maximum capacity. Each joint was failed due to plastification on the wall of the chord member. The strengths of the joints before and after the fire were compared. According to the findings obtained from the numerical results, the strength of tubular T-joints after fire decreases to up to 23.5%. In addition, the temperature distributions on the joints vary depending on the brace-to-chord member ratios and chord wall thicknesses. Residual stress and deformations after fire have a significant effect on the strength of both pipe and box T-joints.

The production of wind energy worldwide has increased 20-fold since 2001. Composite material wind turbine blades are beginning to come out of service in large numbers. In general, these de-commissioned structures, composed primarily of glass fibers in a thermoset matrix and generally between 13 and 80 m long, are demolished and either landfilled or incinerated. This research seeks to establish structural re-use applications for wind turbine blades in civil engineering infrastructure. This paper presents design concepts along with materials and engineering analysis for high voltage electricity transmission structures made from re-used wind turbine blades. This re-use application targets wind blades in the 25 to 50-m overall length range, with single blades considered for use as cantilevered poles, and multiple blades used as replacements for waist-type truss or guyed towers. Strengths of the composite materials are established from coupons cut from de-commissioned wind blades – and section properties are established from blade geometries acquired using LiDAR scanning, through proprietary algorithms developed as part of the research effort. The section analysis is based on two common commercially available blades in the European and U.S. markets: the Vestas V52 and the Clipper C96. The paper reports on preliminary strength design allowables for the typical wind blade laminates and uses these as the basis for design under gravity, wind, and ice loading. Preliminary design of connections and physical mockup testing of these connections are presented.

This study aims to verify which the performance-based design was successfully applied in the construction of the main exhibition hall of the first Hebei Garden Expo, China. Based on the idea of “equality and connectivity” among humans, buildings, and the environment, the exhibition hall was designed using digital shape generation technology, and a special double-skin structure was selected. A bright exterior glass curtain wall separated from the cell-shaped reinforced concrete (RC) structure, not only made the exhibition hall fit into the scenery so well, but also presented an adhesion area with functional links to the RC structure. Joints of the steel tubular truss and the glass curtain wall were optimally designed by means of finite element simulations. During the service of more than a decade, extension of space, function of interactivity, and energy conservation required for a green infrastructure were achieved, highlighting the ecological connectivity of the exhibition hall with the surrounding landscape. The exhibition hall performed synergy of structure and architecture functions and it is still a landmark building in Shijiazhuang, showing an excellent application achievement of the performance-based design.

Αντικείμενο της Διατριβής αποτελεί η αναλυτική διερεύνηση της δυνατότητας βελτίωσης της αντισεισμικής συμπεριφοράς ειδικών δικτυωτών πλαισιακών συστημάτων (Special Truss Moment Frames, STMFs, από χάλυβα) μέσω της ενσωμάτωσης ράβδων κυκλικής διατομής από κράματα νικελίου-τιτανίου (μνήμης μορφής – shape memory alloy bars), οι οποίες αποτελούν εναλλακτικό σύστημα απορρόφησης της σεισμικής ενέργειας στο ειδικό τμήμα (special segment) των πλαισίων. Τούτο καθόσον διαθέτουν την δυνατότητα να ανακτήσουν την αρχική τους (απαραμόρφωτη) γεωμετρία μετά από μηχανική διαταραχή κατά την αποφόρτιση, μέσω του μετασχηματισμού φάσης των κρυσταλλικών δομών (ματερνσιτικής – ωστενιτικής). Ο επικρατών αντισεισμικός σχεδιασμός των STMFs με ειδικό μέρος ευρισκόμενο στο μέσο του ανοίγματος τους (με σκοπό την απορρόφηση σεισμικής ενέργειας) είναι η δημιουργία πλαστικών αρθρώσεων στις τέσσερεις γωνίες. Αυτός ο μηχανισμός προτείνεται να αντικατασταθεί μέσω της παραμόρφωσης των SMAs σε ένα ειδικό μέρος με αρθρώσεις στις κορυφές του. Τονίζεται ότι οι ράβδοι SMA θεωρούνται σε όλες τις αναλύσεις της Διατριβής ως μη λυγηρές, είτε λόγω μεγάλης διατομής είτε λόγω ενίσχυσης μέσω συστημάτων αποφυγής λυγισμού.

Pipe bridges are structures that play an indispensable role in chemical and oil plants. They support cable trays or pipe-carrying material. This study aims to identify the ideal configuration of a pipe bridge through the comparative study of girders with drop hanger and truss arrangements for three different spans. The most efficient arrangement for each span was suitably identified. Through the analysis carried out, it was then identified that the Girder arrangement is suitable for smaller spans such as 15 meters; while the truss arrangement was preferable for longer spans.

In this paper, it is argued that conceptual design in Model Code 2010 should be considered as a design act, rather than a design phase. This creative design act can be defined as an ill-defined problem and co-exists to some extent with the ‘other’ design acts the engineer performs during the design phase. This is illustrated by a case study. A part of the design process for the curved roof of a sports hall is traced. While the team had already decided on the architectural form and the structural concept during the competition, afterwards the roof gradually evolved from concrete vaults to a steel truss system. Several observations are made on the design process and an alternative scheme for the flowchart in Model Code 2010 is proposed.

Standing at a height of 300 m, the Commerzbank Tower was also the tallest skyscraper in Germany and held that title for all of Europe from its erection in 1997 until 2005. The structure boasts a full-height atrium, nine four-story sky gardens, a Vierendeel truss structural system, and a double-skin facade. Together these features create a high-quality indoor environment that is less impactful on the environment because of reduced energy consumption and emissions compared to conventional high-rise office buildings. It is still considered the world’s first ecological office tower which contributes to its design added value, which this chapter presents as a second case study.

The purpose of this paper is to propose a design method when designing a bridge from origami engineering. Origami engineering has the characteristics of "foldable", "high rigidity" and "engineering design".Origami engineering is widely used from interior design to the space field. There are various types, but in this paper, we focus on Yoshimura folds. Focusing on the characteristics of Yoshimura folds, we use it as the main girder of the bridge in this study. Analyze the properties of Yoshimura folds and devise a bridge model. Bridge modeling is determined by the section angle θ, the relationship between span and rise, and the relationship between girder height and span. Make a model and check the folding behavior. Determine the parameters for making a wooden bridge with a span of 8 m. Finite element method analysis and eigenvalue analysis are performed from the determined parameters. Stress analysis and resonance are examined based on the analysis results. Finally designed and produce a wooden footbridge.In this study, we designed and constructed one design proposal using origami engineering. By limiting the material to wood, it became a bridge like this one. However, it can be said that various shapes can be expected depending on the material. In the future, we can expect various designs for deployable bridges using origami engineering.

The “Rives de la Broye” footbridge in Payerne (Switzerland) is the result of a design and construction competition organised by a global contractor on a municipal public domain. In this context, our team composed of an architect, an engineer and a steel contractor proposed a full-steel structure that combines lightness and elegance with the financial requirements of the project owner.

This paper introduces a new approach for the seismic performance evaluation of planar RC walls. Compared to existing assessment guidelines, such as those in ASCE/SEI 41-17, where performance limits are described by plastic rotation or lateral drift, the proposed method uses local (strain) quantities, obtained from computational models. The analyses rely on a user-friendly implementation of the nonlinear truss model for RC structures, which eliminates the need to manually create a line-element representation of a wall and includes a material law for steel accounting for buckling and rupture of reinforcement. The capability of the models to capture common failure patterns for planar walls is validated for a set of six previously tested wall components which experienced a variety of damage modes (bar rupture, boundary element failure, diagonal compression and tension failures). The analytical models accurately predict the lateral strength, deformation capacity and failure modes observed in the tests. A set of acceptance criteria, based on the analytically obtained concrete and steel strains, is then established for the immediate occupancy, life safety and collapse prevention levels, consistent with different levels and types of damage. An initial calibration of the limit values associated with these criteria is proposed and verified using the analytical results for the six walls considered. The results of the proposed assessment methodology applied to the six walls are compared to those obtained using the nonlinear procedures in ASCE/SEI 41-17. The results indicate that ASCE/SEI 41-17 may not accurately describe the deformability of walls exhibiting mixed flexure-shear inelastic deformations. National Institute of Standards and Technology (NIST)National Institute of Standards & Technology (NIST) - USA [70NANB19H060] Published version The research presented in this paper is supported by the National Institute of Standards and Technology (NIST) under award No. 70NANB19H060. Any opinions and findings presented in this paper are those of the authors alone, and do not necessarily reflect the opinions of the sponsor.

This paper presents a graphical method for determining the linearized stiffness and stability of prestressed trusses consisting of rigid bars connected at pinned joints and which possess kinematic freedoms. Key to the construction are the rectangular areas which combine the reciprocal form and force diagrams in the unified Maxwell–Minkowski diagram. The area of each such rectangle is the product of the bar tension and the bar length, and this corresponds to the rotational stiffness of the bar that arises due to the axial force that it carries. The prestress stability of any kinematic freedom may then be assessed using a weighted sum of these areas. The method is generalized to describe the out-of-plane stability of two-dimensional trusses, and to describe three-dimensional trusses in general. The paper also gives a graphical representation of the ‘product forces’ that were introduced by Pellegrino and Calladine to describe the prestress stability of trusses.

Built in 1970, the Illzach bridge is located near Mulhouse in eastern France. It is a single 106 m span bridge carrying two traffic lanes, with two lateral steel trusses and an orthotropic slab wit...