Wind-induced loads over double cantilever bridges under construction

Within the last century the interest in wind-induced loads over civil engineering structures has become more and more important, the reason being that the development of new construction techniques and materials has allowed engineers and architects to design new structures far from the traditional concepts, and in many cases wind actions over these singular structures are not included in the existing codes of practice. In this paper the windinduced static loads over bridges constructed by the double cantilever method during erection stages are considered. The aerodynamic load over a double cantilever bridge under a yawing-angled wind produces a yawing (torsional) moment on the bridge deck, which can lead to undesirable rotation of the deck about the supporting pier. The effects of the wind yaw angle and the length of the deck are analysed. The wind action caused by the presence of sliding concrete forms at the ends of the deck is also studied.

Assessing construction and demolition waste on masonry works to avoid future generation

The difficulty of dealing with construction and demolition waste (CDW) on construction sites is not new and continues to be a significant environmental problem. Currently the CDW collection system in Spain is done in a decentralized manner by each sub-contracted company, being necessary to implement effective waste management measures ensuring a correct management and minimization. During the last years several measures have been launched in order to improve and encourage the reuse and recycling of CDW. A widespread solution for CDW recovery is using them as a landscaping aggregate or for road bases and sub-bases. However, measures encouraging onsite prevention still need to be enhanced. This paper studies the major work stage generating CDW and analyses the categories of CDW produced during its execution. For this, several real building sites have been analysed in order to quantify the estimation of CDW generated. Results of this study show that a significant contributor to the CDW generation on building construction sites in Spain are the masonry works. Finally, a Best Practices Manual (BPM) is proposed containing several strategies on masonry works aimed not only at CDW prevention, but also at improving their management and minimization. The use of this BPM together with the Study and Plan of CDW management --required by law--, promotes the environmental management of the company, favouring the cohesion of the construction process organization at all stages giving rise to establishing responsibilities in the field of waste and providing a greater control over the process. Keywords: construction and demolition waste, management, masonry works, good practice measures, prevention.

Tower of Mart��n Gonz��lez or castle of La Raya (Soria): territory, history, defense and construction / La torre de Mart��n Gonz��lez o castillo de La Raya (Soria): territorio, historia, defensa y construcci��n

Abstract The Tower of Mart��n Gonz��lez, also known as castle of La Raya, is placed in the actual border between the Spanish provinces of Soria and Zaragoza and in the historical limit between the Crowns of Castile and Aragon: this is the reason for its name. The castle dominates the hedge of the plain-moors that surround the Valley of N��gima River. It is a castle with courtyard and a high tower in the western flank. The paper analyzes the castle in four main levels. All references about the castle are studied to draw a historical narration and to relate with the territory and other fortifications, both Castilian and Aragonese. Despite its advanced state of ruin, it preserves many rests that allow making an analysis of its defensive elements and constructive aspects. Resumen La torre de Mart��n Gonz��lez, tambi��n conocida como el castillo de La Raya, se sit��a en el l��mite actual entre las provincias de Soria y Zaragoza y en el l��mite hist��rico entre las coronas de Castilla y Arag��n. Domina el extremo de los p��ramos que circundan el r��o N��gima. Es un castillo de tipo torrej��n con patio de armas y una torre del homenaje adosada a su flanco occidental. El an��lisis contempla cuatro niveles fundamentales para el entendimiento de la arquitectura fortificada. La comunicaci��n revisa la documentaci��n existente sobre los elementos hist��ricos que se ponen en relaci��n, mediante el an��lisis territorial, con el sistema fortificado de frontera. A pesar de su avanzado estado de ruina, conserva restos que permiten realizar una lectura interpretativa de sus elementos defensivos y de sus aspectos constructivos.

The construction of sexpartite vaults in Europe

Sexpartite vaults constitute one of the most interesting chapters in European Gothic architecture. Originally, the use of the square cross-ribbed vault was limited to relatively small spaces, but when the need arose to cover spaces of considerable size, a new vault with very peculiar characteristics appeared. This new vault was a cross-ribbed vault that was reinforced in the centre by a rib that was parallel to the transverse ribs which effectively divided the vault in half. This configuration breaks the side arch into two fragments, creating a pair of windows on each side. The volumetrics of these vaults is extremely complex and the difficulties involved in their construction perhaps explain why they were abandoned in favour of the simple cross ribbed vault, now with rectangular sections. The existence of the sexpartite vault barely lasted more than fifty years, from the end of the XII century and the beginning of the XIII. Towards the end of the 19th century Viollet-le-Duc gave a succinct explanation of this type of vault. A. Choisy also, later, devotes some pages to the French sexpartite vault; since then, the subject has only been broached in a few references in later studies on Gothic architecture. However, despite its short period of existence, the sexpartite vault spread throughout Europe and was used to build important vaulting. Viollet-le-Duc's sexpartite vault could be considered to be the prototype of them all, while it is true that the studies that we have conducted so far lead us to affirm that there is a wide variety of vaults, with different volumetric spaces and different construction strategies. Therefore, we believe that this chapter of international Gothic deserves further study applying the knowledge and resources that are available today. This paper has been written to explore the most significant European sexpartite vaults. New measurement technology has led to a revolution in research into the history of construction, allowing studies to be conducted that were hitherto impossible. Thorough data collection using total station and photogrammetry has enabled us to identify the stereotomy of the voussoirs, tas-de-charges and keystones, as well as the bonding of the surfaces of the severies. A comparison of the construction techniques employed in the different vaults studied reveals common construction features and aspects that are specific to each country. Thus we are able to establish the relationship between sexpartite vaults in different European countries and their influence on each other.

Analysis of the Optimal Sharing of Construction Risk in Public Procurement Contracts

This paper discusses a model based on the agency theory to analyze the optimal transfer of construction risk in public works contracts. The base assumption is that of a contract between a principal (public authority) and an agent (firm), where the payment mechanism is linear and contains an incentive mechanism to enhance the effort of the agent to reduce construction costs. A theoretical model is proposed starting from a cost function with a random component and assuming that both the public authority and the firm are risk averse. The main outcome of the paper is that the optimal transfer of construction risk will be lower when the variance of errors in cost forecast, the risk aversion of the firm and the marginal cost of public funds are larger, while the optimal transfer of construction risk will grow when the variance of errors in cost monitoring and the risk aversion of the public authority are larger

Social risk factors in Spanish youth and their impact on self-concept construction

This paper presents evidence from a psychosocial framework about the relationship among youth, work, and identity construction. The aims of this research were twofold. The first one was to analyze the working conditions of Spanish youth and their impact on individuals' biographies. The second one was to examine the effect of labor-related variables on construction / change of identity elements in Spanish youth. For this purpose, two research techniques were used: the Delphi method (103 experts sample from several entities and organizations closely related to our topic) and deep interviews (15 interviews with youths classified according to their relationship with the work market). Copyright 2007 by The Spanish Journal of Psychology.

Modeling construction time in Spanish building projects

The literature states that project duration is affected by various scope factors. Using 168 building projects carried out in Spain, this paper uses the multiple regression analysis to develop a forecast model that allows estimating project duration of new builds. The proposed model uses project type, gross floor area (GFA), the cost/GFA relationship and number of floors as predictor variables. The research identified the logarithmic form of construction speed as the most appropriate response variable. GFA has greater influence than cost on project duration but both factors are necessary to achieve a forecast model with the highest accuracy. We developed an analysis to verify the stability of forecasted values and showed how a model with high values of fit and accuracy may display an anomalous behavior in the forecasted values. The sensitivity of the proposed forecast model was also analyzed versus the variability of construction costs.

Construction of Intelligent Virtual Worlds Using a Grammatical Framework

The potential of integrating multiagent systems and virtual environments has not been exploited to its whole extent. This paper proposes a model based on grammars, called Minerva, to construct complex virtual environments that integrate the features of agents. A virtual world is described as a set of dynamic and static elements. The static part is represented by a sequence of primitives and transformations and the dynamic elements by a series of agents. Agent activation and communication is achieved using events, created by the so-called event generators. The grammar defines a descriptive language with a simple syntax and a semantics, defined by functions. The semantics functions allow the scene to be displayed in a graphics device, and the description of the activities of the agents, including artificial intelligence algorithms and reactions to physical phenomena. To illustrate the use of Minerva, a practical example is presented: a simple robot simulator that considers the basic features of a typical robot. The result is a functional simple simulator. Minerva is a reusable, integral, and generic system, which can be easily scaled, adapted, and improved. The description of the virtual scene is independent from its representation and the elements that it interacts with.

Acceleration and Deflection Analysis for Class C Edge Protection Systems in Construction Work

The requirements for edge protection systems on most sloped work surfaces (class C, according to EN 13374-2013 code) in construction works are studied in this paper. Maximum deceleration suffered by a falling body and maximum deflection of the protection system were analyzed through finite-element models and confirmed through full-scale experiments. The aim of this work is to determine which value for deflection system entails a safe deceleration for the human body. This value is compared with the requirements given by the current version of EN 13374-2013. An additional series of experiments were done to determine the acceleration linked to minimum deflection required by code (200 mm) during the retention process. According to the obtained results, a modification of this value is recommended. Additionally, a simple design formula for this falling protection system is proposed as a quick tool for the initial steps of design.

Construction of 17-19th century domes in the province of Alicante (Spain): the case of San Juan Bautista in Cox

From the late seventeenth to early nineteenth centuries, many religious temples have been built in the province of Alicante (south east of Spain) with brick domes as their main characteristic feature. Often, the limited data available about these remarkable constructions make rehabilitation interventions become into real research projects, with a high value for their historic conservation over time. The aim of this paper is to show a detailed refurbishment analysis of a religious temple built in 1778, showing the need of preservation of historic buildings as a part of the architectural heritage by establishing a common pattern of materials, geometry and constructive systems, specifically in their domes. In most cases, there was not an architectural project for the construction, that is why the analysis of any documentary and archival sources available is essential to find different ways to proceed on the use and maintenance of these religious buildings.

3D teaching: the ideal complement for professionals in design and construction

Today, the requirement of professional skills to university students is constantly increasing in our society. In our opinion, the content offered in official degrees need to be nourished with different variables, enriching their global professional knowledge in a parallel way; that is why, in recent years, there is a great multiplicity of complementary courses at university. One of the most socially demanded technical requirements within the architectural, design or engineering field is the management of 3D drawing software, becoming an indispensable reality in these sectors. Thus, this specific training becomes essential over two-dimension traditional design, because the inclusion of great possibilities of spatial development that go beyond conventional orthographic projections (plans, sections or elevations), allowing modelling and rotation of the selected items from multiple angles and perspectives. Therefore, this paper analyzes the teaching methodology of a complementary course for those technicians in the construction industry interested in computer-aided design, using modelling (SketchupMake) and rendering programs (Kerkythea). The course is developed from the technician point of view, by learning computer management and its application to professional development from a more general to a more specific view through practical examples. The proposed methodology is based on the development of real examples in different professional environments such as rehabilitation, new constructions, opening projects or architectural design. This multidisciplinary contribution improves criticism of students in different areas, encouraging new learning strategies and the independent development of three-dimensional solutions. Thus, the practical implementation of new situations, even suggested by the students themselves, ensures active participation, saving time during the design process and the increase of effectiveness when generating elements which may be represented, moved or virtually tested. In conclusion, this teaching-learning methodology improves the skills and competencies of students to face the growing professional demands of society. After finishing the course, technicians not only improved their expertise in the field of drawing but they also enhanced their capacity for spatial vision; both essential qualities in these sectors that can be applied to their professional development with great success.

Workshops in ���Construction of Structures I���: A new teaching methodology in the Building Engineering Degree

Both the current economic situation in the construction sector and the continuous normative changes in the building area imply the use of new methodologies to enhance students��� competences in the degree of Building Engineer. The aim of this paper is to present, analyse and discuss the development of constructive workshops as a new teaching methodology used in the subject of Construction of Structures I at the University of Alicante to complement the constructive and technical knowledge acquired by our students and to enhance their communicative and representation skills essential for their professional practice in the future. The used methodology is based on the development of three-dimensional construction details (in groups of 3 or 4 students) to be shown in two A1-pannels exposed in the corridors of the Polytechnic School. Thus, students��� work approaches constructive problems in a global way by discussing simultaneously with teachers and other groups about the most suitable solution on each case. This contribution has multiperspective results and improves criticism of students in different areas, encouraging new learning strategies and active participation. What is more, on-line information and web applications have been used to prepare and organize this kind of workshops, allowing students to use new technologies as a complementary learning methodology. In conclusion, the use of these new workshops in the Degree of Building Engineer stimulates an interactive class versus a traditional lecture where the participative groups�� attitude and the development of oral presentations dissolve the traditional boundaries regarding public communication skills of the students in the Degree.

Controversy between curriculum design and curriculum development of online "highly specialized" education in the field of construction

Nowadays, on a global level, the Higher Education System has a complex and broad horizon of curricular tools to use in the teaching and learning process. In addition to these new educational instruments, full of possibilities, we face specific socio-economic conditions that affect in a significantly way the Curriculum Development in certain knowledge areas (areas traditionally built on a methodology based on a physical presence of students in the classroom). Some areas such as Restoration, Rehabilitation or Construction Pathologies, and the construction sector in general, require very defined and particular knowledge that only a small number of experts claim as specialized training. All these aspects condition the teaching methodology performed in a physical classroom at a university campus (the only option used until recent years) and made us consider the integration of online teaching in these areas too. The present work shows the teaching methodology used for the development of two online courses, where we offer distance learning for "highly specialized" formation in the Edification area (an area where traditionally there was only classroom training). At the beginning, both courses were designed by classroom training, but got a really small number of applications due to the specialized topic proposed. Later, we proposed a "Curriculum Redesign" of the contents, offering an online modality, which implied a significant demand both within and outside the university area. A notable feature of this educational experience is the great spectrum opened for attendees of both courses in the online version. This situation improved significantly the "Curriculum Development" for the student and implied an interesting new proposal on the offered contents and materials (what would have been really difficult to get in a face to face classroom). In conclusion, the absence of certain types of specialized contents in the academic university curricula makes essential to raise new methodologies to save the gap in this area through additional training courses as those analyzed in this paper. Thus, our experience opens a debate on the appropriateness of implementing online training in relation to the face to face training in constructive content subjects and, especially, presents a new scheme, not without controversy, for the curriculum design.

Construction of Structures I in Moodle: a new teaching methodology in the Degree of Building Engineer

The subject of Construction of Structures I studies, from a constructive point of view and taking into account current legislation, reinforced concrete structures used in buildings, through the acquisition of knowledge and construction criteria required in the profession of a Technical Architect. The contents acquired in this course are essential for further professional development of technicians and are closely related to many of the subjects taught in the same or other courses of the Degree in Technical Architecture at the University of Alicante. The aim of this paper is to present, analyze and discuss the development of a new methodology proposed in the mentioned subject, as it supposed an important change in the traditional way of teaching Construction and Structures I. In order to incorporate new teaching tools in 2013-2014, the course has been implemented by using a Moodle software tool to promote blended learning with online exercises. Our Moodle community allows collaborative work within an open-source platform where teachers and students share a new and personalized learning environment. Students are easily used to the interface and the platform, value the constant connection with teachers or other fellows and completely agree with the possibility of making questions or share documents 24 hours a day. The proposed methodology consists of lectures and practical classes. In the lectures, the basics of each topic are discussed; class attendance, daily study and conducting scheduled exercises are indispensable. Practical classes allow to consolidate the knowledge gained in theory classes by solving professional exercises and actual construction problems related to structures, that shall be compulsorily delivered online. So, after the correction of the teacher and the subsequent feedback of students, practical exercises ensure lifelong learning of the student, who can download any kind of material at any time (constructive details, practical exercises and even corrected exams). Regarding the general evaluation system, goals achievement is assessed on an ongoing basis (65% of the final mark) along the course through written and graphic evidences in person and online, as well as a individual development of a workbook. In all cases, the acquisition of skills, the ability to synthesize, the capacity of logical and critical thinking are assessed. The other 35 % of the mark is evaluated by a complementary graphic exam. Participation in the computing platform is essential and the student is required to do and present, at least 90% of the practices proposed. Those who do not comply with the practices in each specific date could not be assessed continuously and may only choose the final exam. In conclusion, the subject of Construction of Structures I is essential in the development of the regulated profession of Technical Architect as they are considered, among other professional profiles, as specialists in construction of building structures. The use of a new communication platform and online teaching allows the acquisition of knowledge and constructive approaches in a continuous way, with a more direct and personal monitoring by the teacher that has been highly appreciated by almost 100% of the students. Ultimately, it is important to say that the use of Moodle in this subject is a very interesting tool, which was really well welcome by students in one of the densest and important subjects of the Degree of Technical Architecture.

Implementation Feasibility of a Digital Nervous System for the Construction Industry: For Efficient and Effective Information Management across the Project Lifecycle

The construction industry has long been considered as highly fragmented and non-collaborative industry. This fragmentation sprouted from complex and unstructured traditional coordination processes and information exchanges amongst all parties involved in a construction project. This nature coupled with risk and uncertainty has pushed clients and their supply chain to search for new ways of improving their business process to deliver better quality and high performing product. This research will closely investigate the need to implement a Digital Nervous System (DNS), analogous to a biological nervous system, on the flow and management of digital information across the project lifecycle. This will be through direct examination of the key processes and information produced in a construction project and how a DNS can provide a well-integrated flow of digital information throughout the project lifecycle. This research will also investigate how a DNS can create a tight digital feedback loop that enables the organisation to sense, react and adapt to changing project conditions. A Digital Nervous System is a digital infrastructure that provides a well-integrated flow of digital information to the right part of the organisation at the right time. It provides the organisation with the relevant and up-to-date information it needs, for critical project issues, to aid in near real-time decision-making. Previous literature review and survey questionnaires were used in this research to collect and analyse data about information management problems of the industry ��� e.g. disruption and discontinuity of digital information flow due to interoperability issues, disintegration/fragmentation of the adopted digital solutions and paper-based transactions. Results analysis revealed efficient and effective information management requires the creation and implementation of a DNS.