Use of grooved clamping plate to increase strength of bolted moment connection on cold formed steel structures

Transcription

1 IOP Conference Series: Materials Science and Engineering PAPER OPEN ACCESS Use of grooved clamping plate to increase strength of bolted moment connection on cold formed steel structures To cite this article: Y D Setiyarto 2018 IOP Conf. Ser.: Mater. Sci. Eng View the article online for updates and enhancements. This content was downloaded from IP address on 26/12/2018 at 02:29

2 Use of grooved clamping plate to increase strength of bolted moment connection on cold formed steel structures Y D Setiyarto Civil Engineering Department, Faculty of Engineering and Computer Science, Universitas Komputer Indonesia, Jalan Dipatiukur No Bandung, Indonesia y.djoko.setiyarto@ .unikom.ac.id Abstract. The purpose of this study was to look at an alternative way of enlarging the strength of the moment connection on cold formed steel structures using the grooved clamping plate. To support the research we use the experimental method of testing the moment connection on the cold formed steel with the addition of grooved clamping plate. Experimental results show that the cold formed steel moment connection using the grooved clamping plate can be significantly increased compared to a cold formed steel moment connection that only increases the diameter of the bolt and the distance between the bolts. From these results, it is known that the addition of the grooved clamping plate at moment connection can give a nominal moment force increase of almost 200%, whereas the addition of bolt spacing and diameter gives only a nominal moment force increase of almost 50%. Of course, this experimental result will be an alternative innovation in terms of enlarging the strength of the moment connection on cold formed steel. 1. Introduction Increasing the power of the moment connection using a bolt is generally done by increasing the number of bolts, increasing the diameter of the bolt, or extending the distance between the bolts. Problems arise when attempts to increase the number of bolts or extend the distance between the bolts are limited by the bending of the flange and lip on the cross section of the cold formed steel profile. Similarly, the relatively thin thickness of the cold formed steel plate causes the bolt diameter enlargement effort to be less significant in increasing the projected area between the bolt rod and the cross section of the bolt hole. The relative thinness of the cold formed steel plate causes the failure of the platen at the bolt joints more often than the shear failure of the bolt [1]. Although there are several other connecting tools such as welding, screws, glue, cold rivets, but the use of bolt tools for moment connection in cold formed steel structures is considered the easiest and more effective in holding larger loads [2, 3, 4, 5, 6]. This paper presents an alternative way to increase the strength of the connection by forming a groove around the connection field by using a grooved clamp plates. The basic idea is that the increase in strength is obtained by the addition of the area of the bearing field already in the bolt hole, using a groove shaped as in Figure 1. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Published under licence by Ltd 1

3 2. Method The moment-connection test is carried out by providing a UTM tension force at the free end of the horizontal lip channel so that there is a moment in the junction area due to the eccentricity between the lower grip and the grip arm. The concept of rotation measurement is to measure the magnitude of the rotation on the horizontal rod expressed as the length of the steel wire being attracted and rolled by the roller on the assistive device. The rolled steel wire will pull the steel cylinder which one end is retained by the spring in the steel pipe and the other end is attached to the LVDT sensor. Thus, the transition of steel cylinders due to the pull of the steel wire will be measured by LVDT and correlate with the magnitude of the rotation of the connection. Test setup and moment connection test instrumentation can be seen in Figure 2. UTM loading is performed using a displacement control system (6 mm / min). Although the connection has strength until rotation reaches more than 0.35 rad, but the ultimate moment used in this research is the moment of connection when rotation 0.05 rad or 20 [7, 8, 9]. Bearing Area Addition of Bearing Area a. Bolts Without Groove b. Bolts With Groove Figure 1. Adding groove to the connection. Figure 2. Test setup dan instrumentation. 3. Result and Discussion The results of the moment connection testing performed can be seen in Figures 3 and Table 1. In a connection rotation of 0.05 rad, the moment connection using 34 mm bolts (Speciment 2) has a momentary power connection (Mu) of knm. The strength of the joint is enhanced by increasing 2

4 the diameter and extending the distance between the bolts (Speciment 3) to produce Mu = knm, or an increase of 46%. If the moment connection plus the use of the clamp plate (Speciment 1), then obtained Mu = 1412 knm or an increase of %. The use of additional plates such as plate plates has been shown to add the area of bearing, even reducing the elongation or bolt hole enlargement in the force direction [5, 10, 11]. If the moment capacity of the used lip channel (Mn) is 9.76 knm, then the connection strength using the clamping plate can be more effective as it is closer to Mn (85.59%). Since the bolt setting for Speciment 1 and Speciment 2 has the same placement and bolt diameter, it is certain that the increased force of the moment connection using this flip plate is due to the addition of the area of contact of the pivot on the groove that occurs during loading. Based on Table 5 it is known that Mu produced the moment connection with the clamp plate, 34.6% is from the bolt bolt mechanism and 65.4% is derived from the bearing mechanism of groove clamping plate. The failure of the moment connection using the clamping plate is marked by the deformation in the groove plane formed, as well as the bolt edge as shown in Figure 4. The existence of elongation in the bolt hole indicates that the friction is relatively small, and the groove field formed is not a means of moving the location of the occurrence of the bearing mechanism, but a means to increase the area of bearing contact. Similarly, fractures are not encountered in the connection system of the platen, either on the groove formed or around the bolt hole. Table 1. Differences in connection strength. No Speciment Use Different With Mu (knm) No. 2 Mn (%) (%) 1 Grooved Clamping Plate Bolt Bolt Grooved Clamping Plate Moment, Mu (kn.m) Bolt Bolt Rotation (rad) Figure 3. Result of moment connection test. 3

5 Bearing Contact with Protrude Bearing Contact with Groove Figure 4. The failure of speciment. As a discussion material in this experimental study, the use of clamp plates at moment connection on cold formed steel will result in 3 forms of failure, namely (a) the bearing mechanism on the bolt rod with the edge of the hole [4], (b) the bearing mechanism between the groove plates with the grooves formed on cold formed steel [8, 9] and (c) the bearing mechanism between the grooves formed on both cold-formed steel surfaces connected [7]. The model of the bearing mechanism of the clamp plate can be seen in Figure 5. Figure 5. Bearing mechanisms on moment connections using clamping plate. 4. Conclusion Based on the observation of the experimental results, it can be concluded that the use of the grooved clamping plate for the moment connection on cold-formed steel structure can increase the strength of the moment connection (Mu) by 188% larger than the unused clamping plate. Increasing the strength of the moment connection (Mu) is caused by the bearing action that occurs in the groove formed. The experimental results for a rotation of 0.05 rad indicate that 65.4% Mu is derived from the bearing action on the plane, the remainder being the bolt action on the bolt rod. The friction mechanism is not found in the connection system. In addition to the tension force on the clamping plate is not provided, the elongation occurring in the bolt hole fastening of the clamping plate is an indication that the friction mechanism does not occur in the connection system. References [1] Rondal J 2000 Cold Formed Steel Members and Structures: General Reports Journal of Constructional Steel Research 55 p [2] Chung K F and Wong M F 2002 Structural Behavior of Bolted Moment Connections in Coldformed Steel Beam Column Subframes Journal of Constructional Steel Research 58 p

6 [3] Dunai L and Foti P 2004 Experimental Behaviour Modes of Cold-Formed Frame-Corners Connections in Steel Structures V [4] Hancock G J 2003 Cold-formed Steel Structures Journal of Constructional Steel Research 59 p [5] Dubina D, Stratan A, Ciutina A, Fulop L and Nagy Z 2004 Strength, Stiffness and Ductility of Cold-formed Steel Bolted Connection Connections in Steel Structures V [6] Dundu M and Kemp A R 2006 Strength Requirements of Single Coldformed Channel Connected Back to Back Journal of Constructional Steel Research 62 p [7] Ali B A, Saad S and Osman M H 2010 Cold Formed Steel Frame with Bolted Moment Connections International Journal of Civil and Structural Engineering 52 p 1-10 [8] Kwon Y B and Hancock G J 1992 Tests of Cold Formed Channels with Local and Distortional Buckling Journal of Structural Engineering 50 p 1-10 [9] Chung K F, Ho H C and Wang M F 2002 An Investigation into Deformation Characteristic of Lapped Connection between Cold-Formed Steel Z Sections International Journal of Steel Structures 5 The Korean Society of Steel Construction (KSSC) [10] Young B and Hancock G J 2001 Design of Cold Formed Channels Subjected to Web Crippling Journal of Structural Engineering 55 p 1-10 [11] Davies J M 2004 Recent Research Advances in Cold Formed Steel Structures Journal of Constructional Steel Research 55 p