Identification of Vehicle Loads on an Orthotropic Deck Steel Box Beam Bridge Based on Optimal Combined Strain Influence Lines

Round 1

Reviewer 1 Report

The paper needs some minor revisions:

- the state of the art is insufficient and should be expanded significantly,

- the abstract should be improved in its language;

- the scale effect of the tests performed should be discussed;

- the choice of the vehicle investigated should be discussed;

- tables and figures should be reported in one piece in one page instead of being divided in two pages;

- The cross section of the bridge is not very clear; why is this type of bridge chosen here?

- the FEM model's characteristics should be illustrated;

- Figure 11 is not clear at all;

- Figure 9 should be deleted.

- Conclusions should be ordered by points.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

In this paper, a method for identifying vehicle loads based on an ideal combined strain influence line was proposed. In order to track the strain response as the vehicles crossed the deck, two different strain gauge types were placed at the lower edge of the deck. For the purpose of detecting axle information, such as the number of axles, wheelbase, and vehicle speed, one type of sensor was installed on the lower edge of the deck between U-ribs. The other kind of sensor, which measured axle weight, was installed on the lower U-ribs.  Secondly, using the least-square method, the strain influence line was found in the structural response beneath the vehicle crossing the bridge with a known weight. Based on a calibrated combined strain influence line, it is possible to determine the unknown vehicle load. To verify the efficiency and anti-noise performance of the suggested method, a numerical simulation and an experimental test were conducted. The obtained results demonstrate that the suggested algorithm performs well in terms of accuracy and noise reduction. The paper is very interesting, and the following are some specific observations:

1.     In equations (11) and (12), the authors must substitute a standard symbol for cv to represent the variation coefficient.

2.    It is not clear how the pi, the practical output of the ith individual in the output layer, is calculated. This should be explained in a detail.

3.      The finite element model considered for the study corresponds to an orthotropic deck steel box girder. Will the same approach be applicable if a concrete deck and girder bridge are used?

4.       An alternative to safeguarding bridges from vehicular loading and its dynamic effects is to install energy-dissipating devices. Such work were reported in the papers like "Vibration control of bridge subjected to multi-axle vehicle using multiple tuned mass friction dampers", International Journal of Advanced Structural Engineering, 8(2), pp. 213-227, 2016. https://doi.org/10.1007/s40091-016-0124-y . A discussion in this regard, taking into account the paper mentioned above and others, would be extremely beneficial to the researchers.

5.     The presentation of the paper needs to be further improved to the level of international journal standards.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf