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Experimental study of debris-induced scour around a slotted bridge pier

Hamidifar Hossein, Nezhadian Damoon Mohammad Ali, Carnacina Iacopo

Acta Geophysica

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2022

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Vol. 70, no 5

2325--2339

EN

One of the most common problems for river engineers is the accumulation of waterborne debris upstream of the bridge piers. In addition to reducing the cross-sectional flow area, debris increases the drag force exerted to the pier and contributes to scour. Several studies have been carried out by previous researchers to examine the usefulness of different types of countermeasures. The effectiveness of these countermeasures is not well understood when debris accumulation occurs. In this study, the effect of debris accumulation on the efficiency of a bridge pier slot, as scour countermeasure, is investigated experimentally. A total of 54 experiments were carried out under different hydraulic and debris geometrical conditions. The results showed that slots were effective in protecting bridge piers against scouring in presence of debris. Depending on the debris shape, the reduction efficiency may increase or decrease for a slotted pier in presence of debris accumulation when compared to the standard pier conditions without debris accumulation. Except for the inverse pyramid shape, the maximum scour is generally more reduced due to sheltering effect when the debris is located on the bed. While debris accumulation can lead to a reduction of the slot efficiency, the slot can be considered a reliable countermeasure against scouring. The outcome of this study can help the design of new bridges affected by large wood debris accumulations.

2

Microstructural Damage Characteristic of a Layer-to-Layer Three-Dimensional Angle-Interlock Woven Composite Under Quasi-Static Tensile Loading

Ma Qian, Wang Ke, Wang Shu-Dong, Chen Hong-Wu, Jin Li-Min, Liu Hua, Qin Xiao

Autex Research Journal

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2020

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Vol. 20, no. 2

121--127

EN

Three-dimensional angle-interlock woven composites (3DAWCs) are widely used for their excellent mechanical properties. The most significant feature is the existence of the undulated warp yarns along the thickness direction, which makes it interesting to study the mechanical properties in the warp direction. The quasi-static tensile behavior of a layer-to-layer 3DAWC along the undulated warp direction was studied by experimental and finite element analysis (FEA) methods. Based on the experimental results, the typical failure mode involving fibers, resin, and their interfaces was found. According to the FEA results, the stress concentration effect, key structural regions, and microstructural (yarn and resin) damage mechanism were obtained, which provided effective guidance for structural optimization design of the 3DAWC with stronger tensile resistance performance. In addition, the three-step progressive failure process of the 3DAWC under quasi-static tensile load was also described at the “yarn–resin” microstructural level.

3

Analiza przęseł obiektów mostowych narażonych na uderzenia pojazdów

Łaziński Piotr, Salamak Marek

Mosty

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2019

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nr 3/4

36--41

PL

Intensywna rozbudowa infrastruktury drogowej w Polsce połączona jest z ciągłym wzrostem natężenia ruchu samochodowego, w tym ciężkiego. Już na etapie budowy obiekty mostowe narażone są na uderzenia pojazdów lub maszyn, co doprowadza do awarii konstrukcji. W trakcie eksploatacji częstymi zdarzeniami są groźne w skutkach wypadki czy kolizje oraz przejazdy pojazdów ponadgabarytowych. Uszkodzenia starych obiektów kolejowych spowodowane są zaniżoną skrajnią, która uwzględnia inne wymagania techniczne z etapu budowy.

EN

The intensive development of road infrastructure in Poland is associated with the continuous increase of traffic intensity, including heavy traffic. Bridge structures are exposed to vehicle or machine impact already at the stage of their construction, which leads to structural failures. Dangerous accidents and collisions as well as heavy and oversized transport are common events during the operation of bridge structures. The damage of old railway structures are caused by understated gauge, which takes into account different technical requirements at the construction stage.

4

The nature of the main structural damage in Boeing 737-400 as identified during overhaul type C

Golda P., Konieczka R.

Zeszyty Naukowe. Transport / Politechnika Śląska

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2016

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z. 90

71--89

EN

In its preliminary part, the article characterises Boeings 737-400 as due to undergo further tests as well as the basic materials used in their construction. It also defines to what extend these materials are prone to damage in the course of their regular use over the planes’ working lives. The object of the analysis is the most prevalent structural damage to the fuselage of the planes discovered during overhaul type C and the definition of the best preventive service. Further on the article categorises the discovered problems and provides their genesis. The main part of the article is devoted to the definition of the sources and reasons for the damage. Consequently, the article forms guidelines how to prevent the occurrence of such and similar damage to the fuselage.

PL

W części wstępnej artykułu zostały scharakteryzowane samoloty typu Boeing 737-400 jako obiekty dalszych badań oraz podstawowe materiały użyte w ich budowie. Jednocześnie określono podatność tych materiałów na uszkodzenia zaistniałe w toku eksploatacji. Przedmiot badań stanowią uszkodzenia strukturalne kadłuba samolotu wykryte podczas przeglądów typu C, jako najbardziej szczegółowych i skutecznych rodzajów obsług. Przedmiotem dalszej analizy są rodzaje wykrytych uszkodzeń strukturalnych kadłuba samolotu oraz ich geneza. Główną część artykułu stanowi określenie źródeł i przyczyn powstania przedmiotowych uszkodzeń. Jednocześnie jest to przesłanka do dalszego określenia właściwej profilaktyki w celu zapobiegania powstawaniu takich i podobnych uszkodzeń samolotu.