Bridge weigh-in-motion system and Structural Health Monitoring using fiber optic sensors

There have been over 3000 bridge weigh-in-motion (B-WIM) installations in 25 countries worldwide, this has led vast improvements in post processing of B-WIM systems since its introduction in the 1970’s. This paper introduces a new low-power B-WIM system using fibre optic sensors (FOS). The system consisted of a series of FOS which were attached to the soffit of an existing integral bridge with a single span of 19m. The site selection criteria and full installation process has been detailed in the paper. A method of calibration was adopted using live traffic at the bridge site and based on this calibration the accuracy of the system was determined.

Extracting bridge frequencies from dynamic responses of two passing vehicles

A conventional way to identify bridge frequencies is utilizing vibration data measured directly from the bridge. A drawback with this approach is that the deployment and maintenance of the vibration sensors are generally costly and time-consuming. One of the solutions is in a drive-by approach utilizing vehicle vibrations while the vehicle passes over the bridge. In this approach, however, the vehicle vibration includes the effect of road surface roughness, which makes it difficult to extract the bridge modal properties. This study aims to examine subtracting signals of two trailers towed by a vehicle to reduce the effect of road surface roughness. A simplified vehicle-bridge interaction model is used in the numerical simulation; the vehicle - trailer and bridge system are modeled as a coupled model. In addition, a laboratory experiment is carried out to verify results of the simulation and examine feasibility of the damage detection by the drive-by method.

Investigating Feasibility of Drive-by Bridge Monitoring by Laboratory Experiments

A potentially powerful drive-by bridge inspection approach was proposed to inspect bridge conditions utilizing the vibrations of a test vehicle while it passes over the target bridge. This approach suffers from the effect of roadway surface roughness and two solutions were proposed in previous studies: one is to subtract the responses of two vehicles (time-domain method) before spectral analysis and the other one is to subtract the spectrum of one vehicle from that of the other (frequency-domain method). Although the two methods were verified theoretically and numerically, their practical effectiveness is still an open question.Furthermore, whether the outcome spectra processed by those methods could be used to detect potential bridge damage is of our interests. In this study, a laboratory experiment was carried out with a test tractor-trailer system and a scaled bridge. It was observed that, first, for practical applications, it would be preferable to apply the frequency-domain method, avoiding the need to meet a strict requirement in synchronizing the responses of the two trailers in time domain; second, the statistical pattern of the processed spectra in a specific frequency band could be an effective anomaly indicator incorporated in drive-by inspection methods.

Monitoring and model updating of an FRP pedestrian truss bridge

This paper presents the results of a real bridge field experiment, carried out on a fiber reinforced polymer (FRP) pedestrian truss bridge of which nodes are reinforced with stainless steel plates. The aim of this paper is to identify the dynamic parameters of this bridge by using both conventional techniques and a model updating algorithm. In the field experiment, the bridge was instrumented with accelerometers at a number of locations on the bridge deck, recording both vertical and transverse vibrations. It was excited via jump tests at particular locations along its span and the resulting acceleration signals are used to identify dynamic parameters, such as the bridge mode shape, natural frequency and damping constant. Pedestrianinduced vibrations are also measured and utilized to identify dynamic parameters of the bridge. For a complete analysis of the bridge, a numerical model of the FRP bridge is created whose properties are calibrated utilizing a model updating algorithm. Comparable frequencies and mode shapes to those from the experiment were obtained by the FE models considering the reinforcement by increasing elastic modulus at every node of the bridge by stainless steel plate. Moreover, considering boundary conditions at both ends as fixed in the model resulted in modal properties comparable/similar to those from the experiment. This study also demonstrated that the effect of reinforcement and boundary conditions must be properly considered in an FE model to analyze real behavior of the FRP bridge.

Evaluation and Testing of a Lightweight Fine Aggregate Concrete Bridge Deck in Buchanan County, Iowa, TR-648, 2016

Internal curing is a relatively new technique being used to promote hydration of Portland cement concretes. The fundamental concept is to provide reservoirs of water within the matrix such that the water does not increase the initial water/cementitious materials ratio to the mixture, but is available to help continue hydration once the system starts to dry out. The reservoirs used in the US are typically in the form of lightweight fine aggregate (LWFA) that is saturated prior to batching. Considerable work has been conducted both in the laboratory and in the field to confirm that this approach is fundamentally sound and yet practical for construction purposes. A number of bridge decks have been successfully constructed around the US, including one in Iowa in 2013. It is reported that inclusion of about 20% to 30% LWFA will not only improve strength development and potential durability, but, more importantly, will significantly reduce shrinking, thus reducing cracking risk. The aim of this work was to investigate the feasibility of such an approach in a bridge deck.

Can the European Union build a bridge over troubled waters? An analysis of the politicised and depoliticised legal approach between the European Union and Cyprus

The Cyprus dispute accurately portrays the evolution of the conflict from ‘warfare to lawfare’ enriched in politics; this research has proven that the Cyprus problem has been and will continue to be one of the most judicialised disputes across the globe. Notwithstanding the ‘normalisation’ of affairs between the two ethno-religious groups on the island since the division in 1974, the Republic of Cyprus’ (RoC) European Union (EU) membership in 2004 failed to catalyse reunification and terminate the legal, political and economic isolation of the Turkish Cypriot community. So the question is; why is it that the powerful legal order of the EU continuously fails to tame the tiny troublesome island of Cyprus? This is a thesis on the interrelationship of the EU legal order and the Cyprus problem. A literal and depoliticised interpretation of EU law has been maintained throughout the EU’s dealings with Cyprus, hence, pre-accession and post-accession. The research has brought to light that this literal interpretation of EU law vis-à-vis Cyprus has in actual fact deepened the division on the island. Pessimists outnumber optimists so far as resolving this problem is concerned, and rightly so if you look back over the last forty years of failed attempts to do just that, a diplomatic combat zone scattered with the bones of numerous mediators. This thesis will discuss how the decisions of the EU institutions, its Member States and specifically of the European Court of Justice, despite conforming to the EU legal order, have managed to disregard the principle of equality on the divided island and thus prevent the promised upgrade of the status of the Turkish Cypriot community since 2004. Indeed, whether a positive or negative reading of the Union’s position towards the Cyprus problem is adopted, the case remains valid for an organisation based on the rule of law to maintain legitimacy, democracy, clarity and equality to the decisions of its institutions. Overall, the aim of this research is to establish a link between the lack of success of the Union to build a bridge over troubled waters and the right of self-determination of the Turkish Cypriot community. The only way left for the EU to help resolve the Cyprus problem is to aim to broker a deal between the two Cypriot communities which will permit the recognition of the Turkish Republic of Northern Cyprus (TRNC) or at least the ‘Taiwanisation’ of Northern Cyprus. Albeit, there are many studies that address the impact of the EU on the conflict or the RoC, which represents the government that has monopolised EU accession, the argument advanced in this thesis is that despite the alleged Europeanisation of the Turkish Cypriot community, they are habitually disregarded because of the EU’s current legal framework and the Union’s lack of conflict transformation strategy vis-à-vis the island. Since the self-declared TRNC is not recognised and EU law is suspended in northern Cyprus in accordance with Protocol No 10 on Cyprus of the Act of Accession 2003, the Turkish-Cypriots represent an idiomatic partner of Brussels but the relations between the two resemble the experience of EU enlargement: the EU’s relevance to the community has been based on the prospects for EU accession (via reunification) and assistance towards preparation for potential EU integration through financial and technical aid. Undeniably, the pre-accession and postaccession strategy of Brussels in Cyprus has worsened the Cyprus problem and hindered the peace process. The time has come for the international community to formally acknowledge the existence of the TRNC.

Clinton Multimodal (U. S. 30 Mississippi River Bridge) Study, 2003

The purpose of this memorandum is to document the benefit-cost analysis of the river crossing concept alternatives described in the "Concept Alternatives Technical Memo." Benefit-cost studies are designed to measure, in dollars, the potential positive or negative impacts of large-scale construction projects. The concept alternatives analyzed include improvements to the Union Pacific Railroad (UPRR) River Crossing and the U.S. Highway 30 (U.S. 30) River Crossing.

State-of-the-Art Methods for Design of Integral Bridge Abutments, HR-227, 1981

The routine use of integral abutments to tie bridge superstructures to foundation piling began in this country about 30 years ago. Kansas, Missouri, Ohio, North Dakota, and Tennessee were some of the early users. This method of construction has steadily grown more popular. Today more than half of the state highway agencies have developed design criteria for bridges without expansion joint devices.