Evaluation of Harmony Search Optimization to Predict Local Scour Depth around Complex Bridge Piers

Abstract

One of the main causes of bridge collapse may be flood flow scour near piers. Several experimental and local field investigations were carried out to study scour depth. However, existing empirical equations do not commonly provide accurate scour prediction due to the complexity of the scour process. Physical and economic considerations often lead to bridge foundation constructs which included a pier column based on a pile cap supported by an array of piles. Piers with this configuration are referred to as complex piers. A few studies have been done on complex bridge pier scour depth estimation. Such efforts may be classified into theoretical and empirical equations. This paper investigates local scour around complex bridge piers by using harmony search algorithm under clear water conditions. Statistical indices such as the coefficient of determination (R2), root mean square error (RMSE), mean absolute error (MAE), mean absolute percentage error (MAPE), and bias were used to evaluate the performance of these methods. By designing laboratory tests, 82 experimental data points were measured by authors. Also 615 experimental data sets with the same measured experimental conditions were collected from published literature and used for optimization. The results show that the developed HS model can predict scour depth better than other equations according to statistical indices.

Experimental Modeling and Evaluation Sediment Scouring in Riverbeds around Downstream in Flip Buckets

“…A comparison of experimental and regression model results (a) Equation 4, and (b) Equation 5In Figure 6(a), the linear regression fit was made between the experimental values and the calculated values presented for the dimensionless parameter (Equation (4)), so that the correlation coefficient R 2 and the regression line slope α equaled 0.97 and 1.01, respectively, which suggested a very good performance of the relationship. Moreover, in Figure 6(b), the same comparison was made for Equation (5), so that the correlation coefficient R 2 and regression line slope α equaled 0.93 and 0.98, respectively, which also showed that the relationship had a good performance.…”

“…This structure is an economical alternative to other conventional dissipators such as stilling basins, etc. [4,5]. So far several studies have been carried out to address scouring downstream of flip bucket jets by Bormann and Julien [6]; Jafari and Khiavi [7], Mason and Arumugan [8], Amanian and Urroz [9], Stein et al [10], Afify and Urroz [11] and Cordier et al [12].…”

Literature review of bridge structure's optimization and it's development over time

“…ant colony [77], water flow, and an ensemble of musicians [78]. Some illustrations of the metaheuristic techniques in addition to genetic algorithm (GA) [79,80], harmony search (HS) [81], firefly algorithm (FA) [82], Tabu search (TS) [83], artificial bee colony (ABC) [84], teaching-learning-based optimization (TLBO) [85], particle swarm optimization (PSO) [86], bat algorithm (BA) [87], cuckoo search (CS) [79], and many others. To characterize metaheuristic algorithms, taxonomies founded on specific features of algorithms are created [88], Nature-inspired vs. non-nature-provoked objective functions, population-based vs. trajectory-based objective functions, and dynamic vs. static objective functions are only a few examples.…”

A Hybrid Intelligence Approach to Enhance the Prediction Accuracy of Local Scour Depth at Complex Bridge Piers

“…Because of the complicated process of scour around bridge piers, the local scour depth at complex pier (LSCP (is a complicated phenomenon and hence its accurate predictions are a critical issue for the design of bridge foundations. In other words, overestimation of LSCP may lead to extra construction costs and even bridge failure around their foundations [3].…”