Experimental dynamic analysis of the arch road bridge

The paper presents an experimental dynamic analysis of the existing road bridge across the Labe river at Valy village in the Czech Republic. The observed structure is a bridge with 6 spans 23.1 m, 31.5 m, 84.0 m, 31.5 m and 23.1 m long. The horizontal load-bearing structure is a composite structure with two main steel girders and a lower reinforced concrete deck. The load-bearing structure is reinforced in the main span by the arch, this structural system is also called the Langer beam. The experiment was realized in three stages. The first one was performed in May 2020 before its opening, the second stage of the described experiment was realized in August 2020 and the third one was carried out in April 2021. The main purpose of the first stage was to determine in detail the natural frequencies and mode shapes of the whole bridge horizontal load-bearing structure also including the arch. The electrodynamic shaker, that was located on the bridge deck in the quarter of the main bridge span, was used for excitation of the bridge vibration. The measured characteristics of the natural vibration were compared with the calculated ones. Based on this comparison, the theoretical bridge model was verified. Basic objective of the second experiment stage was to verify new approach to dynamic response measurement – radar interferometry realized by two synchronized radars. The vibrations of the bridge caused by the standard road traffic and also by pedestrians were observed concurrently by both radar interferometry and classical approach realized by high sensitive piezoelectric accelerometers. The experiment was focused on the main span of the bridge only and the levels of forced vibration were observed primarily. However, the fundamental natural frequencies were also evaluated. The third stage was carried out by classical approach only. Again, the bridge vibration caused by the usual road traffic and pedestrians were measured in the main bridge span only because this section of the bridge was the most dynamically sensitive. Again, the levels of forced vibration were observed and the fundamental natural frequencies were determined. The evaluated natural frequencies from all three experiment stages were consequently compared.

Design and Physical Detection of Bridge Tower and Externally Prestressing Cable for Existing Bridge Strengthened by A Cable-Stayed System

With the continuous development of economy, the increasing traffic volume has brought greater burden to highway bridges. In this paper, a Yellow River Bridge is taken as an example. The cracking and deflection of the box girder of the main bridge have affected the structural performance requirements of the bridge operation. Based on this situation, the cable-stayed system is used to reinforce the bridge, and the construction process of bridge tower, cable saddle, steel anchor box and external beam is described in detail. The theoretical calculation and practice show that this method can effectively strengthen the bridge structure, and the cable-stayed system reinforcement method, as a mature, reasonable and operable construction technology, provides relevant reference for the reinforcement research of similar bridges.

Analytical and Measured Effects of Short and Heavy Rail Cars on Railway Bridges in the USA

The overall number of railcars recorded in the North American railcar fleet from 2010 to 2015 increased about 5%; the number of all 130 tonne (286,000 lb) gross weight railcars (heavy axle load (HAL) railcars) increased 19%. The increase in shipments in short railcars increases the loading on railway bridges, especially the 12.8-m railcars, commonly used to ship sand and cement, which is approximately a 25% increase in load per unit length compared to 16.2-m coal cars. Significant differences between maximum effects of shorter railcars and common 16.2-m railcars were predicted in analysis for bridge spans longer than 18.3 m. The differences were more prominent on spans 24.4 m and longer. This study presents analytical and measured effects of freight railcars on a two-span truss bridge, with spans of 61 m and 33.5 m, and a 35-m riveted steel deck plate girder (DPG) bridge. The investigation confirmed that short railcars cause higher load effects on main bridge components: the 35-m riveted steel DPG has 28% higher stresses at mid-span, while in the truss, the difference in stresses depends on the location of the member and ranges from 15 to 35%.

Added values of the local timbers materials for main bridge frame structures utilizing laminating composites technology

The objectives of this article are to seek the opportunity to enhance the local Indonesia timber material physical performances (encompassing the low-class quality of III and IV timbers with the Modulus of Elasticity (MOE) = 5,000 - 9,000 MPa) utilizing laminated composite technology to become higher-class timber quality (class II) with the Modulus of Elasticity (MOE)> 15,000 MPa so that it can be used as an alternative material for constructing the bridge mainframe structures (girder beams) especially for the Indragiri Hilir regency, Riau Province, Indonesia. This regency needs several hundred small-medium bridges for connecting 20 districts, 39 wards, and 197 villages using local materials such as local timbers. This laminating technology is not a new technology but the utilization of this technology for constructing the main bridges structures is challenging and limited to the implementation in the civil construction industrial sector. This study composed 2 types of the low-class quality (lcq) of timber materials (such as Shorea sp and Shorea peltata Sym) and 2 types of medium class-quality (mcq) ones (Dipterocarpus and Calophyllum) for constructing the main bridge structures. Based on the laboratory test results utilizing 80% of lcq materials and 20% mcq ones, these composite timber materials may increase the timbers MOE by 145% to 166% from the existing MOE value of the mcq solid timbers. Based on the simulations these laminated composites wooden bridge girders 2 x (70x20) m2, these timber materials have passed all the tests and the application of this technology may improve the lcq timber values and it could be used for an alternative material of the bridge girder's main structures.

Visual picture of the world in the reflection of modern media

The article Visual picture of the world in the reflection of modern media is a part of the scientific work devoted to the analysis of the methods of disclosure of the plurality of meanings by means of visualise and ways of their influence on the viewer's perception. The analysis offered for discussion of questions allows to trace in a new way process of search of expressiveness of screen culture, including off-screen media content and art projects. We also consider how with the advent of computer technology, modern media, United in a single screen culture, seek to reflect the picture of the rapidly changing world in its mosaic, in the development of end-to-end time. Special attention is paid to the visual form of plastic images of cinema and television, which largely predetermined the path of development of visual perception of the world through sensory knowledge of the global process-taking place in the world. The author highlights the question of how the screen directs a person on the path of solving problems on links/trailers, lifehacks / commercials, running lines, while providing the right to choose, and new judgments, sometimes non-trivial, and sometimes false. Revealing the connections of new communicative means the author offers the concept of the birth of a new civilization, where online communication, information exchange, media messages, various formats-not just a way to change the transmission of information, but civilization with its own laws and rules of communication, with a new language, based on technical and English language terms, expanding the possibility of merging different cultural layers, with its philosophy and aesthetics, where visualization is a way to control the viewer's attention. Various forms of editing in its broadest sense become the main "bridge"of the whole" composition" of the world order, where the division into the size of the event series, media persons is decisive. Various forms of editing in its broadest sense become the main "bridge"of the whole" composition" of the world order, where the division into the size of the event series, media persons is decisive. To reveal a number of issues, the author draws Parallels with the cinema, highlighting the similarities and differences in the specifics of the spectacular nature of the two components of modern screen culture.

Statistical survey of existing reinforced and pre-stressed bridge types for the AT-CZ region within the "ATCZ190 SAFEBRIDGE" Project

<p>Advanced modeling of structures using combination of non‐linear finite element methods (NLFEM) and reliability analysis is a strong tool for realistic assessment of structures. NLFEM simulation has been recently a well‐established approach to the analysis of concrete structures since the response of the structure can be simulated quite realistically. In combination with fully probabilistic approaches, one can consider the randomness of input parameters such as material, technological and environmental characteristics that can have a direct impact on economic aspects during structural lifetime. However, guidelines fully describing NLFEM modeling of structures and safety formats are not available until now. In the framework of the European Project INTERREG AUSTRIA‐CZECH REPUBLIC "ATCZ190 SAFEBRIDGE", a number of existing bridges are carefully selected to be studied and modeled with NLFEM on deterministic and stochastic levels based on the upcoming Austrian standard ON B4008‐2. The assessment of structures will be described and documented in detail and the results will assist the development of a guideline. This guideline targets to help the engineering community perform accurate NLFEM analysis and to assist the structure's owners to check the accuracy of the assessment process. The current paper focuses on the presentation and discussion of statistical information about road and railway bridges provided by the main bridge operators in both countries. Moreover, the most commonly addressed structural characteristics of bridges within the program region are summarized and the further future steps of the project are briefly described.</p>

Main span closure for the New Samuel de Champlain Bridge (NSCB) - An innovative alternative closure using a temporary king-post to accelerate construction

<p>Signature Saint Laurent (SSLC) is the consortium comprised of SNC Lavalin, Flatiron Constructors Canada, Dragados USA and EBC, that selected the design and construction for the New Samuel de Champlain Bridge (NSCB) in Montreal, Canada.</p><p>The NSCB’s construction schedule was the major challenge for a successful project completion. The geometry of the main bridge is complex, with an asymmetric stay cable arrangement and a unique transverse behavior with three independent corridors connected by crossbeams, involving the location of the stay cable anchorages. This geometry questioned the constructability and the stringent schedule requirement. The subject of this paper is relevant to this conference as it pertains to an innovative construction method for cable-stayed bridges.</p><p>The back span was fully erected on temporary towers in advance, followed by the main span which was to be built with heavy lifting equipment in cantilever sequentially from the main single pylon towards to the East approach. A set of three gantries erected the preassembled segments from the ground to the tip of the deck, where they were connected to the previous segment.</p><p>To expedite the construction, an innovative method was developed to erect some segments from the opposite end with cranes from the ground, with a stick-built conventional method. The closure location was therefore shifted by 50 meters (four segments) towards the pylon. These segments would be supported with temporary stay cables anchored to a 36-meter high king-post on top of the deck. The king-post would be sitting on top of the deck, supported temporarily by shoring towers to reduce the demands in the superstructure and adjacent pier.</p><p>This erection system can serve as an alternative method to expedite construction for long span single tower cable stayed bridges, by erecting segments with a temporary stay tower from the opposite end, therefore reducing schedule constraints.</p>