Lock Gates Research Articles

Simplified Analytical Methods to Analyze Lock Gates Submitted to Ship Collisions and Earthquakes

Abstract This paper presents two simplified analytical methods to analyze lock gates submitted to two different accidental loads. The case of an impact involving a vessel is first investigated. In this situation, the resistance of the struck gate is evaluated by assuming a local and a global deforming mode. The super-element method is used in the first case, while an equivalent beam model is simultaneously introduced to capture the overall bending motion of the structure. The second accidental load considered in this paper is the seismic action, for which an analytical method is presented to evaluate the total hydrodynamic pressure applied on a lock gate during an earthquake, due account being taken of the fluid-structure interaction. For each of these two actions, numerical validations are presented and the analytical results are compared to finite-element solutions.

A simplified analytical method to estimate the resistance of plane lock gates impacted by river barges

This paper presents a simplified analytical method to evaluate the resistance of a single plating lock gate impacted by a river barge. The approach is based on the assumption that the gate behavior may be divided into two successive phases. At the beginning of the collision, local crushing of some structural elements occurs concomitantly with small overall elastic motion of the entire gate. Then, when the penetration of the barge into the gate becomes important, a global plastic mechanism develops over the entire structure. In addition to the membrane and bending deformations occurring classically in such collisions, the particular flat shape of the striking barge bow leads to shear deformations near the gate edges. For all these deformation modes, closed-form expressions of the gate resistance are derived for both local and global deformation phases by applying the upper-bound method. These analytical developments are then validated through comparisons with numerical solutions obtained from non-linear finite-element simulations.

A simplified analytical method to evaluate the seismic pressure on plane lock gates

This paper presents a meshless method to perform the seismic analysis of a plane lock gate. The approach is based on the analytical derivation of the total hydrodynamic pressure, with due consideration for the gate flexibility. In particular, the flexibility of the gate and the fluid–structure interaction are taken into account in the calculation of the equivalent force that has to be applied on the gate to model the action of the water. To reach this goal, the Rayleigh–Ritz method is first used to determine the modal properties of the dry structure. This is achieved by using mode shapes extracted from the beam theory as generating functions. The results obtained in this way are validated by comparison with numerical solutions. The second step consists in performing the dynamic analysis of the gate by deriving a weak form of the equilibrium equation. Based on the Galerkin method, a matrix formulation is derived and the Newmark integration scheme is used for the evaluation of the pressure during the earthquake. Here again, non-linear finite element simulations including water modeling are carried out to corroborate the analytical developments. In addition, the lumped-mass method is also investigated and a criteria is proposed to check its applicability. Finally, some concluding remarks are given to perform more easily the seismic analysis of lock gates.

Simplified analytical methods for the crashworthiness and the seismic design of lock gates

The thesis presents two simplified analytical methods for the design of lock gates submitted to accidental loads. The developments are concerned with vessel collisions and earthquakes. They are mot...

A review of technical solutions and simulation approaches for ship collisions with lock gates

Lock gates are frequently found at inland waterway locks and sea navigation locks. Entering a lock with a ship is a challenging manoeuvre, which can potentially lead to the ship colliding with the lock gate. Such collision may permanently damage the gate causing the lock operation to be disrupted and the ship transport to be delayed. Consequently, it is important to design for the possibility of a ship colliding with the lock gate to ensure its operability as well as the safety of the operation. In order to do so, a variety of recommendations and standards exist, which are however neither unified nor require the assessment of the lock under a ship collision on a mandatory basis. Therefore, this paper presents the current developments in assessment approaches for ship collisions with lock gates as well as current gate protection practices. The paper concludes with a recommendation of assessment approaches, which can be used to identify safe lock gate approach velocities in the case of existing locks or collision resistant structural layouts for new buildings of lock facilities.

Planktonic food web structure and dynamic in freshwater marshes after a lock closing in early spring

We conducted a weekly survey at two stations of a French coastal marsh during the transition from winter to spring, when the sea lock gates were closed. Field measurements and laboratory experiments were combined in order to describe the structure and dynamics of planktonic food webs. Physico-chemical parameters were measured, and food web typology was described for the first time in the marsh using plankton biomass and internal flux assessment. Both stations changed from a “biological winter” to food webs identified as “multivorous” and passed through to a herbivorous food web. However, food web structure differed significantly between the two stations at the end of the study. Station A remained as a multivorous food web, while station B changed to a strong multivorous food web. After the sea lock gates closing (end of March), an increase in phosphorus concentrations in the water column at station B may have controlled bacterial and phytoplankton development and could explain, at least in part, the differences between the two stations. Our study suggests moreover that differences in water renewal between the two stations could have been responsible for the differences observed. Sea lock gates closing seems to be responsible for the rapid changes observed in food web structure, suggesting that the effects of human hydraulic management on ecosystem functioning in marshes is not yet well understood.

The history and replacement of lock gates

Wooden canal lock gates require routine replacement after around 30 years. From the 1960s in England, there was a move by the then waterway authority, British Waterways (now the Canal and River Trust), towards standardisation to make construction simpler and cheaper. Today, the conservation of the individual character of each canal has been identified as a way of encouraging greater use of canals. However, the return of lock gate design to its historic form is sometimes seen as unsuitable for locks that have statutory protection. Information about the original design and subsequent alterations of lock gate construction for individual canals should be an important factor in deciding what type of replacement gates should be used. This paper looks at the history of navigational locks, putting their development into an international context. It then considers the reasons for replacing lock gates with those of a traditional design, and the archive material available for the replication of wooden lock gates in England.

The Cryptogenic Red Alga <i>Bangia Atropurpurea</i> in Lough Derg, River Shannon, Ireland

The filamentous and euryhaline red alga Bangia atropurpurea (Rhodophyta, Bangiophyceae) is a littleknown member of the Irish aquatic flora. Although a common freshwater species in the northern hemisphere, it seems that the lower Shannon Navigation is one of the principal freshwater localities for the species in Ireland. It was recorded from thirteen sites in Lough Derg in 1972 and in the 2010 survey reported here at 40 sites including islands and navigation buoys as well as on lock gates. It attaches to rocks and other hard surfaces immediately above and below the waterline. It may have been introduced to Lough Derg on the hulls of commercial vessels. Changes in climatic conditions, eutrophication, competition from other filamentous algae and fluctuating lake levels are all pressures that could affect the sustainability of Bangia within the Shannon Navigation. Nevertheless, this study shows that B. atropurpurea has persisted for at least 40 years in Lough Derg and remains widespread despite highly variable environmental conditions.

THE CRYPTOGENIC RED ALGA BANGIA ATROPURPUREA IN LOUGH DERG, RIVER SHANNON, IRELAND

The filamentous and euryhaline red alga Bangia atropurpurea (Rhodophyta, Bangiophyceae) is a little-known member of the Irish aquatic flora. Although a common freshwater species in the northern hemisphere, it seems that the lower Shannon Navigation is one of the principal freshwater localities for the species in Ireland. It was recorded from thirteen sites in Lough Derg in 1972 and in the 2010 survey reported here at 40 sites including islands and navigation buoys as well as on lock gates. It attaches to rocks and other hard surfaces immediately above and below the waterline. It may have been introduced to Lough Derg on the hulls of commercial vessels. Changes in climatic conditions, eutrophication, competition from other filamentous algae and fluctuating lake levels are all pressures that could affect the sustainability of Bangia within the Shannon Navigation. Nevertheless, this study shows that B. atropurpurea has persisted for at least 40 years in Lough Derg and remains widespread despite highly variable environmental conditions.

A lightweight, self‐adaptive lock gate designation scheme for data collection in long‐thin wireless sensor networks

ABSTRACTConstrained by the physical environments, the long‐thin topology has recently been promoted for many practical deployments of wireless sensor networks (WSNs). In general, a long‐thin topology is composed of a number of long branches of sensor nodes, where along a branch each sensor node has only one potential parent node toward the sink node. Although data aggregation may alleviate excessive packet contention, the maximum payload size of a packet and the dynamically changing traffic loads may severely affect the amount of sensor readings that may be collected along a long branch of sensor nodes. In addition, many practical applications of long‐thin WSNs demand the exact sensor readings at each location along the deployment areas for monitoring and analysis purposes, so sensor readings may not be aggregated when they are collected. This paper proposes a lightweight, self‐adaptive scheme that designates multiple collection nodes, termed lock gates, along a long‐thin network to collect sensor readings sent from their respective upstream sensor nodes. The self‐adaptive lock gate designation scheme balances between the responsiveness and the congestion of data collection while mitigating the funneling effect. The scheme also dynamically adapts the designation of lock gates to accommodate the time‐varying sensor reading generation rates of different sensor nodes. A testbed of 100 Jennic sensor nodes is developed to demonstrate the effectiveness of the proposed lock gate designation scheme. Copyright © 2011 John Wiley & Sons, Ltd.

Ultimate strength of stiffened plates with a square opening under axial and out-of-plane loads

The high strength to weight ratio and high stiffness to weight ratio of stiffened plates find wide application in aircraft structures, ship structures, offshore oil platforms and lock gates. The strength and stability of stiffened plates is highly influenced by openings and initial imperfections. The main objective is to study the behaviour of stiffened steel plates with openings up to collapse and to trace the post-peak behaviour under axial and out-of-plane loads. Four stiffened steel plates with a square opening were fabricated for testing. Angle sections were used as stiffeners. Imperfections in the plate, stiffener and overall imperfection of the whole panel were measured. All fabricated panels were tested to failure. A finite element (FE) model was developed for the analysis of stiffened plates with initial imperfections and validated with the test results. Parametric studies were conducted using the developed FE model, and interaction curves and equations were developed for the design of stiffened plates with initial imperfections and openings. The interactive effect for stiffened panels with a square opening was found to be linear, with proportional reduction of the ultimate axial load carrying capacity due to the constant out-of-plane load.

Lock gates improve passage of small‐bodied fish and crustaceans in a low gradient vertical‐slot fishway

Abstract A modified ‘lock’ mode of operation was trialled within a low‐slope (3.1%) vertical‐slot fishway to improve passage of small‐bodied (<60 mm long) native fishes in the Murray River, Australia. Significantly greater numbers of three small‐bodied native fish and two crustacean species ascended the fishway during lock operation than during standard operation. Up to 9700 small‐bodied fish and crustaceans exited during the lock operation in a single 2‐h replicate. A deficiency of the temporary lock conditions was that large‐bodied fish and their young‐of‐the‐year (>50 mm long) did not ascend during the study. Considerable experimental work is required at other sites and at higher fishway slopes before widespread retro‐fitting of lock gates. Nevertheless, these results highlight new options for potentially improving the ecological performance of existing pool‐type fishways and new facilities.

인천항 기능 재배치에 따른 갑문의 대기 시뮬레이션 연구

인천항에서는 인천대교 건설을 계기로 남외항 건설을 추진함과 더불어 인천 내항 등의 기능 재배치가 추진되고 있다. 본 논문은 기능 재배치 계획에 따라 2011년과 2015년의 해상교통량을 추정하고, 내항의 갑문 운용에 따른 선박의 대기시간을 항만운용 시뮬레이션에 의하여 분석하여 내항에 기항하는 선박들의 체선 체화비용을 산정 분석하고자 하였으며, 최종적으로 2011년부터 2015년까지 내항에 기항하던 컨테이너선들의 남항/남외항으로의 이전에 따른 경제적 효과를 평가하고자 한다. 주요한 연구결과는 다음과 같다. (1) 갑문 이용율이 약 <TEX>$7\sim8%P$</TEX> 낮아졌다. (2) 갑문 대기시간 및 체선 체화비용이 약 25%P 절감되는 효과가 나타났다. (3) 자문 이용료와 선석 이전에 따른 항로 단축 편익 등을 제외하고 갑문 운용에 따라 발생되는 체선 체화비용은 연간 약 8억원의 절감효과가 있었다. Due to the construction of Incheon Grand Bridge, there is driven a necessity for rearranging the function of Inner Port with the development of Outer South Port. In this paper, I'd like to simulate the port operation levels of Lock Gate in Inner Port with estimating the traffic volumes of 2011 and 2015, which will reveal the Demurrage Cost and the Accumulation Cost of Freight in Inner Port. Finally I will evaluate the economic movement effects of the container ship's calling from Inner port to South Port/Outer South Port from 2011 to 2015. The results are as followings ; (1) The average utilization of Lock Gates are reduced by <TEX>$7\sim8$</TEX> percentage point. (2) The mean queueing value are saved by 25 percentage point. (3) The Demurrage Cost and the Accumulation Cost of Freight except Lock Gate charges and the Benefit of Routeing Reduction are saved about 800 million Won annually.

Crashworthiness analysis of a lock gate impacted by two different river ships

The objective of this paper is to present an analytical model for the crashworthiness analysis of plane lock gates impacted by river ships. The model is able to assess the indentation by the colliding ship at impact point, to detect possible failure in impact vicinity and to estimate the actions on gate bearings. These latter are calculated by assuming the crash to a quasi-static load, and linear reactions distributions along the bearings. The gate geometry, the bow shape of the colliding ship, its initial velocity and the impact location on the gate, are taken into account. The ships are assumed to be quite rigid with respect to the gate. The modeling has been developed with Matlab. Results of impact of one given lock gate with two different ships: a passenger vessel and a carrier, are compared with FEM results. Impact forces and maximum indentation are well matched. Actions on bearings can be locally rather different because of their time dependence and the non-linearity of their distributions.

인천항 갑문의 운영 수준에 관한 연구

In inner harbour of Incheon port, there are two lock gates (50KT, 10KT) which have two gates per lock gate in inner/outer sides except a gate in inner harbour side of 10KT. Due to the lack of the fore-mentioned gate, the use of 10KT lock gate is suspended in energy 3 years for regular maintenance. Now an additional gate is under construction in order to improve the efficiency of the 10KT lock gate. This paper will be aimed to evaluate the operational utilization levels of lock gates in present and future. The operational utilization levels of lock gates in 1998 are evaluated 0.2119 in 10KT lock gate, 0.2061 in 50KT lock gate which were considered the 46.5 closed days every 3 years for 10KT regular maintenance. The levels are estimated to 0.2246(10KT), 0.2539(50KT0 in 2006 and 0.2241(10KT), 0.2560(50KT) in 2011. The levels of 50KT lock gate in 2011 are evaluated to be more rapidly increased up to 24.5% from the levels in 1998.

Crashworthiness analysis of a lock gate impacted by two different river ships

The objective of this paper is to present an analytical model for plane lock gates crashworthiness analysis. The model is able to assess the indentation by the colliding ship at impact point, possible failures in impact vicinity and actions on gate bearings. These latter are calculated by assuming the crash to a quasi-static load, and linear reactions distributions along the bearings. The gate geometry, the bow shape of the colliding ship, its initial velocity and the impact location on the gate are taken into account. The ships are assumed to be quite rigid with respect to the gate. The modelling has been developed with Matlab. Results of impact of one given lock gate with two different ships: a passenger vessel and a carrier, are compared with FEM results. Impact forces and maximum indentation are well matched. Actions on bearings can be locally rather different because of their time dependence and the non-linearity of their distributions.

Conversion Of A Commercial Dock For Use ByLeisure Craft

Port Managers and Engineers around the world must consider the best means and methods to maintain, or preferably increase, income while satisfying the changing requirements of their customers. Since the early 50's commercial vessels have increased in size and capacity. This has resulted in a growth in the number of deep-water berths. To be a valued asset such facilities require a major investment, however, the traditional impound docks are the losers in these developments due to the associated reduction in demand from smaller commercial vessels. This reduction in use results in a commodity that is uneconomical therefore removal of the risk is inevitable. But the removal of an impound dock is an expensive option and difficult to justify financially. Throughout the UK a number of redundant commercial docks have been converted to marinas for leisure craft by providing associated ancillary services together with constructing a new entrance and installing new lock gates. At the Port of Dover, Granville Dock is an impound dock that has recently been converted to satisfy the needs of leisure craft. This conversion was achieved with a surprisingly low financial investment. This paper considers the options open to the Port Management and the methods adopted to satisfy the needs of the future users of the marina. Items such as the availability of experienced skilled craftsmen and the statutory health and safety aspects of a pair of modified mitre gates for the Port Management are discussed. The completed entrance gates have allowed the conversion of Granville Dock to operate as a successful anchorage for leisure craft.

Event Tree Analysis of Lock Closure Risks

The use of event trees and subjective probabilities in risk analysis is illustrated via a case study: the estimation of the probability of closure of Poe Lock on St. Marys River (Sault Ste. Marie, Mich.) because of vessel accidents and other nonstructural failures. The risk of closure is needed to determine the benefits of building a second Poe-class lock at that location. An event tree structures the risk analysis. Probabilities associated with the branches of the tree were developed from a combination of historical data and subjective probabilities. The latter were obtained in workshops with navigation experts. This paper summarizes the risk analysis, and discusses the difficulties associated with obtaining the necessary probabilities. It was found that a 30-day closure could occur about once every 50 years. The results are most sensitive to assumptions concerning how often ships hit lock gates.

Evaluation of the effectiveness of corrosion protection of sheet piling and lock gates of hydraulic structures

Evaluation of the effectiveness of corrosion protection of sheet piling and lock gates of hydraulic structures

On the Prototype Testing and Computer Simulation of St. Lawrence Seaway Hydro-Mechanical Lock Gate Drives

This paper presents the computer simulation and the prototype testing of hydro-mechanical drives for mitre gates in St. Lawrence Seaway navigation locks. For the computer simulation, the technique of Power Bond Graph is adopted to obtain the mathematical model of the lock gate drive. A digital computer is used to predict the performance of the lock gate under the actual operating environment. The model takes into account the friction load, wind load, load due to water surging, inertia load and water resistance load. Dynamic performance measurements on a prototype hydro-mechanical mitre gate drives in St. Lawrence Seaway while in operation were carried out. Good correlation exists between the simulation and prototype test results for pressure and torque transients and also in the operating time for gate opening and closing. Based on this investigation, recommendations are made on a single constant power hydraulic drive of 25 HP for operating St. Lawrence Seaway lock gates most economically.