Load Cell Test Pada Fondasi Jembatan Suramadu

At present, Suramadu Bridge is the longest bridge in Indonesia, having 5.438 m length. The uniqueness of this bridge is the three parts which divide the bridge, those are approaching bridge, main bridge, and causeway. This bridge also provides a special lane for motorists outside of the bridge. For the feasibility test of these bridges, it requires a test to the load to verify the real carrying capacity which is able to be borne by the bridge. Article present a case of foundation which has a large dimension and carrying capacity, by the testing method that is done very limitedly; such as Statnamic and Load Cell Test, or Osterberg Cell Test. Based on the result of the Load Cell test - first phase, a decision to implement Load Test second phase is made. Because it is proposed to use a grouting on the tip of foundation, Load Cell second phase is implemented before and after the grouting. From the results of Load Cell Test second phase, it seems that the implementation of Grouting does not significantly increase the carrying capacity, but give a large contribution on the carrying capacity of friction

Dynamic actions on bridge slabs due to heavy vehicle impact on roadside barriers

The use of roadside safety barriers in Italy has changed in recent years: the number of installed devices has increased, and so have their stiffness and resistance. These changes were necessary because early barrier design was inadequate to contain and redirect heavy vehicles. The change in barrier design led to an increase in stiffness and resistance; consequently, the action transferred to the structure by the device increased. The need for resistance on the bridge slabs can be too high because the peculiar action of the roadside barriers was not adequately taken into account in the oldest bridge design codes. In addition, characterizing the actions transferred to the bridge slab is difficult because of the dynamic nature of vehicle impacts on roadside barriers. Given the impossibility of performing a full-scale laboratory test for every bridge deck, the use of computational mechanics applied to dynamic impact/interaction problems is one of the best ways to establish these actions in the project phase. Research was conducted into the use of a three-dimensional finite element model of the bridge slab-barrier-vehicle system to perform a numerical simulation of the impact, according to the procedure used for the roadside barrier homologation crash test, described in the European Standard EN 1317

Practical considerations regarding results from static and dynamic load testing of bridges

Bridge tests are a helpful tool for bridge assessment and evaluation. Both in the case of a static and dynamic load testing, each element of the test: the load selection and application, the creation of a numerical model to follow the progress of the test or to check the validity of the test results, the measurement process itself and the comparative analysis of experimental results and calculations could be a source of errors in the bridge final evaluation if these errors and uncertainties are not properly considered. The article presents some of the most important factors that may bring errors in the interpretation of the test results and their comparison to targeted values or values derived from a numerical model. This, at the end, may result in the adoption of decisions that are not accurate and appropriate. The selected sources of feasible errors are presented with the division into static and dynamic loading tests. The presented examples of bridge load testing show how the use of improper test methods could lead to significant errors in bridge assessment and evaluation and, consequently, to wrong decisions.Peer ReviewedPostprint (published version

Analysis and design of a modular multilevel converter with trapezoidal modulation for medium and high voltage DC-DC transformers

Conventional dual active bridge topologies provide galvanic isolation and soft-switching over a reasonable operating range without dedicated resonant circuits. However, scaling the two-level dual active bridge to higher dc voltage levels is impeded by several challenges among which the high dv/dt stress on the coupling transformer insulation. Gating and thermal characteristics of series switch arrays add to the limitations. To avoid the use of standard bulky modular multilevel bridges, this paper analyzes an alternative modulation technique where staircase approximated trapezoidal voltage waveforms are produced; thus alleviating developed dv/dt stresses. Modular design is realized by the utilization of half-bridge chopper cells. Therefore, the analyzed converter is a modular multi-level converter operated in a new mode with no common-mode dc arm currents as well as reduced capacitor size, hence reduced cell footprint. Suitable switching patterns are developed and various design and operation aspects are studied. Soft switching characteristics will be shown to be comparable to those of the two-level dual active bridge. Experimental results from a scaled test rig validate the presented concept

A barrier or bridge? Serious problems revealed in the UK citizenship test

Thom Brooks has examined the UK citizenship test and finds that it is highly irrelevant to living in this society, has many inconsistencies, and suffers from serious gender imbalance. To make matters worse, changes to the test this year have transformed it from being a practical trivia quiz to being purely trivial. Greater care needs to be taken to ensure balance and consistency, and it is worth reconsidering the purpose of the test

An integrated capacitance bridge for high-resolution, wide temperature range quantum capacitance measurements

We have developed a highly-sensitive integrated capacitance bridge for quantum capacitance measurements. Our bridge, based on a GaAs HEMT amplifier, delivers attofarad (aF) resolution using a small AC excitation at or below kT over a broad temperature range (4K-300K). We have achieved a resolution at room temperature of 10aF per root Hz for a 10mV AC excitation at 17.5 kHz, with improved resolution at cryogenic temperatures, for the same excitation amplitude. We demonstrate the performance of our capacitance bridge by measuring the quantum capacitance of top-gated graphene devices and comparing against results obtained with the highest resolution commercially-available capacitance measurement bridge. Under identical test conditions, our bridge exceeds the resolution of the commercial tool by up to several orders of magnitude.Comment: (1)AH and JAS contributed equally to this work. 6 pages, 5 figure

Automated Pin-Dot Marking Effects on A709-Gr50 Steel Plate Fatigue Capacity

During fabrication of multi-piece steel bridge assemblies, markings are often made on the steel surface to identify/track individual pieces or to provide reference for fabrication layout or later erection. Automated marking methods such as computer numerically controlled (CNC) pin-dot marking offer fabrication efficiencies; however, for marked steel sections subjected to frequent or repeated loading (i.e. bridge girders) many code specifications require experimental testing to verify any marking effects on fatigue capacity. In this study, the effects of automated pin-dot markings on the fatigue capacity of A709-Gr50 bridge steel are experimentally investigated from 13 specimens considering 2 marking frequencies (corresponding to marking speeds of 50in./min and 10in./min), 2 applied stress ranges (35ksi and 45ksi), and 2 material orientations (both longitudinal and transverse plate rolling directions). Results from the 13 high-cycle fatigue tests, along with other fatigue test results from the literature indicate that the surface markings from the automated marking systems have no effect on the fatigue capacity of the A709-Gr50 plate. All marked specimens achieved higher fatigue capacities than would be expected for unmarked specimens meeting the AASHTO fatigue detail category ‘A’ designation

Review of Armed Offenders Squad and Special Tactics Group fitness policy for the New Zealand Police : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Exercise and Sport Science at Massey University, Wellington, New Zealand

Phase One: Web based survey questionnaire. Recruitment into the New Zealand Police’s Armed Offenders Squad [AOS] and Special Tactics Group [STG] depends on successful completion of selection courses, as detailed in their respective physical fitness policies. Importantly, these physical assessments must be justified as being relevant and representative of the necessities of job duties. Therefore, as part of a review of the physical fitness policies of the AOS and STG of the New Zealand Police, Phase One of this research sought to objectively determine similarities and relationships between the AOS and STG, and the relevance of physical selection tasks utilised. A web-based survey questionnaire was developed to: 1) provide a demographic profile of the AOS and STG; 2) identify why candidates chose to participate in selection; 3) identify potential barriers for gaining entrance into the AOS and STG; 4) identify physical preparation methods for selection tests; 5) identify troublesome tests; and 6) establish the validity between fitness assessments and the perceived relevance of job demands. A total of 179 AOS (N = 298) and 35 (N = 38) STG members volunteered to participate in the on-line survey document. The main findings revealed that the 12 minute bridge test had the lowest perceived relevance of all selection tests, while the rope pull-up had moderate perceived relevance but was coupled with a high failure rate. This provided evidence to further research the aforementioned assessments in Phase Two of this project. Abstract Review of AOS and STG fitness policy for NZ Police 2 Phase Two: Analysis of the rope pull-up and twelve minute rotational bridge. The rope pull-up and 12 minute bridge test are physical assessments utilised to identify whether STG members possess appropriate levels of physical fitness required to perform their role. Due to a lack of empirical research, and Phase One findings, this study sought to: 1) determine whether the rope pull-up is a suitable assessment tool to assess operational climbing ability; and 2) determine whether the 12 minute rotational bridge test is a safe and suitable assessment of core endurance. Nineteen STG members (mean ± SD; 40 ± 5 y, 184 ± 5 cm, 93.6 ± 7.4 kg, 25.4 ± 1.9 kg·m²) volunteered to participate in this research. Surface electromyography was utilised to measure peak muscle activity of the brachioradialis, biceps brachii, mid-deltoid, upper pectoralis major, mid-trapezius, lower trapezius, latissimus dorsi and infraspinatus during rope pull-up, ladder climb and rope climb tasks. Average muscle activity and signal frequency of the rectus abdominis, external oblique, internal oblique, mutlifidus, lumbar erector spinae, thoracic erector spinae, latissimus dorsi and mid-deltoid were measured during the 12 minute bridge test. Results revealed significantly higher activation of the pectoralis major during the ladder climb when compared to the rope pull-up (81.2 vs. 47.1 %MVIC), and of the pectoralis major (102.6 vs. 47.1 %MVIC) and infraspinatus (81.9 vs. 57.4 %MVIC) during the rope climb, when compared to the rope pull-up (all, P .05), indicated that muscular fatigue was minimal. Based on the present study, the rope pull-up was deemed non-appropriate to assess operational climbing ability; while the rotational bridge served as a practical endurance assessment of all major muscles involved in core stability, with the 12 minute duration not likely to cause fatigue related injury