*2.1. General Concepts*

The equivalent in-cast connecting method is commonly used in traditional prefabricated shear wall systems which fails to restore the structural function once being damaged in the earthquake. The proposed HES mainly consists of the energy dissipation zone (ED), the stiffness lifting zone (SL) and the horizontal connecting zone (HC) as shown in Figure 2. The HES could horizontally connect two adjacent walls (Figure 2a), the steel plates in the ED zone and SL zone both utilize bolt connection which could be fast replaced after damage in the earthquake and the resilient structural performance is obviously enhanced. The low-yield-strength steel plates are employed in the ED zone mainly dissipating seismic energy. As depicted in Figure 2d–f, the SL zone is composed of the shear stiffness lifting plate, the flange plate, functional bolts, and the buckling restrained plates. The diameter of the functional bolt bar is set to be smaller than that of the circle hole in the shear stiffness lifting plate and this deviated value is the shear displacement threshold. By this threshold control system, the HES exhibits a controlled two-stage mechanical behavior. As depicted in Figure 2, the obvious shear deformation of the HES could be investigated when the in-plane lateral deformation of two adjacent walls are observed in the earthquake. In the first stage, when the shear displacement is smaller than the displacement threshold the functional bolts would not contact the shear stiffness lifting plate and the SL zone has no contribution to the performance of the HES, only the ED zone dissipating the input seismic energy. In the second stage, when the shear displacement is smaller than the displacement threshold, the SL zone would begin to work and the shear stiffness and bearing capacity of the HES increase again. The adjacent walls would be assembled again becoming a strengthening system and the lateral bearing capacity of shear wall system would increase again, which could protect the structure in the large and super-large earthquake.

Note: ① Connecting end plate; ② high-strength bolts; ᬇ the shear stiffness lifting plate; ᬈ the flange plate; ᬉ functional bolts; ᬊ the buckling restrained plate; ᬋ the backing plateL; ᬌ energy dissipation plate; ᬍ bolts; ᬎ the shear wall; ᬏ the HES

**Figure 2.** Detailed instruction of the HES system. (**a**) The wall connection, (**b**) assembly model, (**c**) cross-section, (**d**) disassembled model, (**e**) lateral stiffness lifting zone, (**f**) threshold control system.

The shear wall and the HES are assumed to be rigid pieces as shown in Figure 3. The deformation of the HES could be computed approximately by Equation (1) when achieving the horizontal displacement of shear walls.

**Figure 3.** The shear deformation of the HES. (**a**) The boundary condition, (**b**) calculation shear deformation of the HES according to the drift displacement.

The drift ratio is a significant parameter defined in many specifications, which is utilized to evaluate structural performance. Therefore, the limited shear deformation of the HESs could be calculated.

$$
\Delta\_{\mathbb{S}} = 0.\mathsf{5} \cdot \mathsf{6} \cdot L = 0.\mathsf{5} \cdot \Delta\_{\text{lU}} \cdot L/H \tag{1}
$$

where, Δ*hw* is the horizontal displacement of the shear wall, Δ*s* is the shear deformation of the shear wall, θ is the drift ratio, L is the width of the shear wall, H is the height of the shear wall.

#### *2.2. The Expected Failure Mode of the HES*

The low-yield-point steel plates (LY 100) the yield stress of which is 100 MPa, are utilized in the ED zone. In order to ensure the bearing capacity and shear sti ffness of the SL zone, Q345B is utilized the yield stress of which is 345 MPa. The threshold control displacement should be reasonably established to ensure that the ED zone and the SL zone could perform well in sequence. Furthermore, the threshold displacement could be adjusted according to the requirement of the expected structural performance, by changing the hole diameter in the shear sti ffness lifting plate. In addition, the shear sti ffness and strength of the shear sti ffness lifting plate could be e ffectively enhanced by adding the flange plate on both sides. Simultaneously, the functional bolts are designed to come to failure in the second stage and the other parts of the SL zone are in elastic. When the ED zone and the functional bolts are damaged in the earthquake, they could be fast and easily replaced, largely enhancing the structural resilient performance. Therefore, the ED zone is expected to dissipate the input seismic energy firstly and the functional bolts are expected to fail with high ductility.

In order to clarify the mechanical mechanism of the HES, simplified models are used in finite element modelling analysis. The lateral connection of the HES to the wall is considered to be rigid. The bolted connection of the steel plates in the ED zone is also considered to be a rigid connection. The threshold control displacement of the typical specimen of HES is set to be 3 mm. On the basis of the simplification, this expected failure mode would be validated by numerical analysis.

#### **3. Model Development and Validation**

The finite element analysis is an e fficient way to predict the performance of testing specimens. The software ABAQUS was employed to simulate the typical hysteretic behavior of the HESs. This numerically modelling method is validated by successfully simulating the cyclic behavior of one low yield strength steel shear plate damper tested by Zhang et al. Using this modelling method, the performance of the HESs are predicted and evaluated.

#### *3.1. Finite Element Model for The HESs*

The model and the boundary conditions are depicted in Figure 4. The shell element S4R is used to model the behavior of the steel plates in the ED zone including their buckling. Eight-node-three-dimensional solid element (C3D8R) with reduced integration and hourglass control is utilized to simulate functional bolts, the flange plate and the shear sti ffness lifting steel plates. The overall meshed model includes a total of 40,444 elements. A typical surface-to-surface contact with a penalty algorithm is employed between the functional bolts and the shear sti ffness lifting plate. A hard contact pressure-over closure relationship is adopted to model the normal contact behavior and the friction coe fficient is set to be 0.2 to simulate the tangential slip behavior. The same contact setting is used between the surfaces of buckling restrained steel plates and shear sti ffness lifting steel plates. In addition, the geometric nonlinearity is considered to model the intermittent contact behavior in the SL zone. The circular part and the bolts in the SL zone are more elaborately meshed. Considering the computational e fficiency and reliability the mesh size of the HES is the same as above which is appropriate for this analysis.

**Figure 4.** The finite element model for the HES.

#### *3.2. Material Constitutive Models*

The von Mises yield criterion and bilinear model are utilized for simulating the behavior of the ED zone made of low yield point steel (LP100) and the SL zone made of Q345B. When the strain ε of the steel sheet is less than the ultimate strain, the actual stress σ of the steel sheet is equal to the elastic modulus multiplied by the strain ε; when the strain ε of the steel sheet is greater than the ultimate strain, the actual stress σ of the steel sheet is equal to the elastic modulus multiplied by the ultimate strain. With the advancement of structural health monitoring technology, high precision strain measurement can be obtained [37,38] to guarantee the quality and reliability of stress calculation under complicated load bearing situation. The elastic modulus of the steel is set to be = 2.05 × 10<sup>5</sup> MPa, the Poisson's ratio of steel is taken as 0.3 [39,40].

#### *3.3. Validation of the Finite Element Model*
