## 4 Technological Advancements
### Manual to Automatic Detachable Inter-Modular Connections  
Inter-modular connections cannot be removed once locked, making it challenging to reuse the IMU in the event of accidental damage during servicing. Because of this issue, researchers created bolted and pin types of IMCs through SHS, as shown in Figure 4a-d. They consider the constructional tolerance brought on by the automatic mechanical IMC and the repetitive use of IMUs via a replaceable or detachable IMC. The threaded block of the lower IMU is tightened to the bolt of the upper IMU using a long twisted rod that the authors designed for the detachable IMC shown in Figure 4a [70] and pinned joint shown in Figure 4d [76]. Although these joints are detachable, tightening the bolts inside the columns requires a lengthy rod tool, which is laborious; hence, the bolt diameter or screwing length is typically small, reducing their seismic and lifting capacities. Consequently, as shown in Figure 4b, a mechanical replacement has recently been developed to address these difficulties. A new, low-carbon mechanical IMC integrates the IMU horizontally and vertically through linearly translating the pins and transfer plates. An extended twisting rod is used in this connection to operate the mechanical arrangement of the components  
Figure 2: Manual IMC. (**a**) column–column welded [54]; (**b**) rotary connector [60, 61, 63]; (**c**) beam-beam bolted [66, 67]; (**d**) beam-beam and column–column bolted [64]; (**e**) fully bolted plug-in connector [65]; and (**f**) column–column pre-tensioned [68, 69] IMC. and pin them together [77; 78]. As soon as the bolt is turned, horizontal pins instantly lock into place and establish a solid connection between the IMUs on the exterior and interior. These joints perform reliably in seismic and pullout operations. Because these bolted joints are only helpful in tightening or demounting corner and hollow columns, researchers created a new way to connect the beams rather than the columns without the need for any tightening equipment, as depicted in Figure 4c. The onsite fastening connections are replaced by a robust mechanical interconnecting system that allows for twist, tilt, and slide adjustments [79]. However, the joining system cannot withstand the tensile stresses, which forces the use of pri  
Figure 4: Detachable IMC. (**a**) screw bolted [70]; (**b**) auto-pin screw [77; 78]; (**c**) beams sawed [79]; and (**d**) pinned bolted [76] IMC. Figure 3: Automatic IMC. (**a**) slider locker tongue [57]; (**b**) self-lock bolt shaft [74]; (**c**) pin plug-in devised [72]; (**d**) circular plug-in devised [73]; (**e**) slider block [71]; (**f**) lock-tongue slider [70]; and (**g**) automated self-lock bolt shaft [75] IMC. SMA bracing and SMA bolts' IMC minimizes the residual stresses and is a recyclable solution [80,81]. Through self-centering, the haunch bracing system proposed in Figure 6c improved the IMCs' ductility [65]. Recently, a slider device with reusable bonded rubber units was devised [82, 83, 84, 85, 86]. After 5 mm of torsion and translation, they may dissipate 80% of the earthquake energy through friction. The haunch bracing with a plug-in IMC transferred the failure from the joints to the beams and demonstrated superior self-centering systems that may be used in high seismic zones for mid- to high-rise PFISBs. Moreover, the PFISBs' and system's full strength can be achieved using a double-skin steel shear wall, as shown in Figure 6b [87]. The composite action of the Corefast 2D and 3D walls increases the fire resistance while attempting to prevent the lateral force damage, as shown in Figure 6f [6]. This is a functional lateral force-resisting system because it delays the structure's yield, increases the elastic stiffness with a yielding wall panel, and prevents out-of-plane buckling prematurely while causing column tearing and strength degradation due to local buckling [87].