**1. Introduction**

According to available data, all concrete arch bridges featuring a span exceeding 300 m worldwide utilize rigid-frame arch bridge structures [1]. The Tian'e Longtan Grand Bridge, which is presently under construction, boasts a main span reaching an impressive 600 m. With an increase in span for rigid-frame arch bridges, structural stress becomes increasingly complex [2], necessitating advanced requirements for bridge design principles and construction control methodologies. Scaled model experimentation serves as an efficacious approach to ascertain the genuine structural status of arch bridges under loadbearing circumstances [3], providing benefits such as elevated safety, robust control over test conditions, and abbreviated test durations.

Researchers have conducted studies on many large bridges around the world [4–7] focusing on the design of scaled bridge tests. The efficiency and accuracy of the loading system, as an essential component of scaled bridge tests, are some of the critical factors affecting the success of these experiments. Currently, research on loading systems in scaled

**Citation:** Fan, Y.; Zhou, J.; Luo, C.; Yang, J.; Xin, J.; Wang, S. Research on Loading Scheme for Large-Scale Model Tests of Super-Long-Span Arch Bridge. *Buildings* **2023**, *13*, 1639. https://doi.org/10.3390/ buildings13071639

Academic Editor: Andrea Benedetti

Received: 15 May 2023 Revised: 22 June 2023 Accepted: 27 June 2023 Published: 27 June 2023

**Copyright:** © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

bridge tests conducted by scholars both domestically and internationally can be roughly divided into three categories:


In summary, traditional model test loading systems have limitations, such as limited loading point numbers, large counterweight volumes, and low loading accuracy [16–19]. To address these issues, a 1:10 scale model loading system for the main arch ring of the 600-m main span of Tian'e Longtan Grand Bridge was designed. An innovative array-type, selfbalancing pulley-group loading system and counterweight optimization algorithm were proposed. This loading system offers advantages, including small counterweight volume, long-term stability, elimination of repeated adjustments during multi-point loading, and high loading accuracy. Our aim is to provide a reference for the design of reduced-scale model tests for similar bridges in the field of engineering structures, overcoming the aforementioned limitations in existing loading systems.
