Structural Behaviour of Metakaolin Geopolymer Concrete Wall-Type Abutments with Connected Wing Walls

is study work is related to exploring the role of connected wing walls in changing the behaviour of a metakaolin geopolymer wall type abutment when acted upon by all the forces that are generally applied on a short-span bridge.emodelling of abutmentwith connected wingwalls is done using the STAADProV8i SS6 software and all the loading applied for the analysis as per IRC: 6-2016.emodelling is done using the 4-noded plate elements for all the members, and the plate elements here are meshed using the quadrilateral meshing feature. e behaviour of the metakaolin geopolymer wall-type abutment is analyzed using various models with changing the basic parameters such as length of the wing walls, height of the walls, number of lanes on the bridge, and type of live load on the bridge. e various results are obtained in the form of bending moments from all the cases, which show us some really interesting behaviour of the abutment wall and the wingwalls. As the length of the wingwalls is increased, they take upmore horizontalmoments than the abutment wall and the deection behaviour of the wingwalls is way dierent than that of cantilever wall, and hence, it shows that the design aspects of the wing walls need to be checked. Also, the connected wing walls cause horizontal moments in the middle of the abutment wall, which is an interesting result; as now, it proves that after casting wing walls monolithically to the abutment wall, the design of the abutment wall cannot be done as cantilever wall, and we need to take care of this horizontal moment by providing required reinforcement. Also, as the length of the wing walls is short, the torsional moments become critical.


Introduction
e construction of bridges has played a major part in the development of our society and civilization. e bridges nowadays are analyzed and designed very cautiously. e analysis part of the bridge system is much more impotent than the design part. e advancement in the stability analysis of the bridge system has reached the behaviour study of the abutments and the wing walls. Abutments are vertical structures, classi ed as substructure component of a bridge system. ey are used to retain the earth behind the structure. e abutments are subjected to the dead loads, live loads from the bridge superstructure, and the lateral pressures mainly from the approach embankment. In a bridge, the wing walls are adjacent to the abutments and act as retaining walls. ey can be parallel to the bridge deck or perpendicular or may at some angle, depending on the requirements. ey are generally constructed of the same material as those of abutments. e walls can be independent or integral with the abutment wall. e integral wing walls have an in uence on the behaviour of the abutment wall; hence, the length, thickness, etc., parameters are adopted carefully after proper design and checks. Wing walls are provided at both ends of the abutments to retain the earth lling of the approaches. e studies about con gurations of the wing walls a ecting the behaviour of the bridges integral with abutment have shown that the connection between the wing wall and the abutment creates a better stable system that can resist loads better [1][2][3]. Some of the studies are in the direction of seismic resistance of the integral abutment bridge and also the backfill soil effect [4][5][6][7][8].
e material used in the construction of the bridge system is also a very important part of the study and needs to explore more and more. When China clay (kaolin) is heated at a higher temperature, a by-product called metakaolin is created. Metakaolin is a very effective pozzolanic substance used in concrete. Metakaolin was effectively included in the concrete used to build a number of sizable dams in Brazil in the 1960s. To enhance certain qualities of cement concrete, metakaolin is utilized in place of OPC. e current hot topic in the construction material industry is the metakaolin geopolymer concrete. MGPC is a green construction material as it does not contain cement, and hence, the emission of CO 2 and other GHGs is nil. e use of this material in the construction of any big structure needs a thorough investigation and tests in the laboratories to prove its mechanical and engineering abilities [9][10][11]. e cube strength and other engineering properties of this material are calculated by various researchers, and here, in this study, those values are used to create the material in the software and then the material is used in further study.

General Design Data.
is study will be done by analyzing an abutment with connected wing walls. e geometric parameters of the walls are calculated and are listed as follows: (1) e density of soil, assumed as surcharge and backfill, is taken as 18 kN/m 3 , and the safe bearing capacity of the soil is taken as 200 kN/m 2 . (2) e thickness of the walls is taken from cantilever wall design, which has given the thickness of the walls according to their height. Here, in the problem, for lesser complication in analysis, the thickness of wing walls and the abutment wall is taken the same. So, the thickness of the walls for different heights is as follows: (3) e whole system of abutment with connected wing walls is taken on rigid foundation. (4) e thickness of the deck slab is taken from an existing bridge, and it is 950 mm at the center gradually reducing to 800 mm at the edges. (5) e span of the bridge is taken as 11 meters, and it is considered that it has unyielding supports with no bearings.

Cases for Analysis.
e variations considered in the basic parameters for analysis are as follows: (1) Wall Height-8 meters, 10 meters, and 12 meters (2) Wing Wall Length-3 meters, 5 meters, and 7 meters So, as per the variations taken for analysis, there will be total 36 cases.

Model Characteristics
(i) e modelling and analysis of the problem are done using the STAAD Pro V8i SS6 software. (ii) e model is made using 4-noded plate element for all the members, i.e., abutment wall and wing walls, and assigned the material property as concrete, as shown in Figure 1. (iii) e width of the abutment wall is taken as 8 meters and 15 meters for 2-lane and 4-lane models, respectively. (iv) e plates are finely meshed using the quadrilateral meshing feature of the software. So, to get better accuracy in the results, the mesh size is kept at 0.5 × 0.5 meter. (v) e thickness of plates is varying from top to bottom in every model and is assigned gradually to every mesh strip from top to bottom, so as to provide the required shape of the walls. (vi) e support for all the bottom nodes of the walls is assigned as a fixed support, as it is taken in the problem that the base of the walls is rigid. (vii) A beam of size 100 × 100 mm is modelled over the abutment wall, as shown in Figure 1. (viii) It is assigned the material property as metakaolin geopolymer concrete, which is created in the software, and provided the required data such as Young's modulus and Poisson's ratio from previous researches [12][13][14], as shown in Figure 2. is is modelled to allow the application of vertical and horizontal loads on the abutment wall.

Load Calculations
(i) All the loads, except the soil and wind loads, are applied on the beam. e soil and wind loads are applied to the plates directly. (ii) e load combinations are formed as per IRC-6: 2016,

3.1.
Results. All the models were analyzed, and the results are presented in the form of tables in this section. e locations

Comparison of Moments. 3.3. Deflected Shapes of Models.
e typical deflected shape of the walls under the provided loading is shown in Figure 4

Variation in Horizontal Moments in Abutment Wall
(i) It is indisputable from Tables 5 and 6 that for 2-lane width the mid. horizontal moment (Mx(mid)) in the abutment wall increases rapidly as the length of the wing walls increases from 3 m to 7 m. It is in the range of 11-18%, 24-40%, and 38-59% for the

Conclusions
e results obtained from the present are thoroughly studied, and from the scope of this work, the following conclusions are drawn: (i) e connectivity of the abutment and the wing walls induces horizontal moments, which are very critical at the connecting edge. So, the horizontal moments in the walls need to be taken under design considerations. Data Availability e data used to support the findings of this study are included within the article.

Conflicts of Interest
ere are no conflicts of interest among the authors. Advances in Materials Science and Engineering 9