Ultimate Tension Load Research Articles

Experimental Study of Structural Performance of Precast Concrete Insulated Sandwich Panels with Cruciform Cross Section GFRP Connectors

This study investigated the structural performance of precast concrete insulated sandwich panels with cruciform cross section glass fiber-reinforced polymer (GFRP) connectors, based on tensile and shear tests. 5 tensile specimens and 4 shear specimens were fabricated and tested. The load-displacement relation and failure mode of the specimens were analyzed. The results revealed that the average ultimate tension load of the tested specimens with single GFRP connector was 13.14kN with concrete splitting or concrete partial cone failure. For the shear specimens, the average ultimate shear load was 14.83kN with rupture failure of GFRP connector. Furthermore, durability of sandwich panels was investigated, by fabricating and testing 48 tensile specimens with GFRP connectors immersed in tension load had sufficient safety in different design situations.

Experimental investigation of the axial strength of glued-in rods in cross laminated timber

This paper presents results from an experimental assessment of glued-in rods in cross laminated timber (CLT). For the purposes of the study more than 60 pull–pull tests were performed, where the specimens varied in terms of bonded-in length (from 80 to 400 mm), rod diameter (16–24 mm) and rod-to-grain angle (parallel and perpendicular). Several different failure modes that are not common for other applications of glued-in rods (e.g., a failure between CLT layers) were obtained for the analysed CLT specimens. It was found that these failure mechanisms can substantially influence the obtained ultimate tension loads. At the end, the experimental results were compared with empirical and semi-empirical equations for estimating the pull-out strength of glued-in rods in structural timber and glulam. The comparison showed that most of the existing equations overestimate the ultimate tension loads for specimens with the rod parallel to the grain and underestimate the ultimate tension load for specimens with the rod perpendicular to the grain. The results vary because the possible CLT failure modes were not included in previous studies. Further studies are proposed to improve the equations for glued-in rods in CLT.

Tension Performance of Metal-Plate Connected Joints of Chinese Larch Dimension Lumber

Tension tests of metal-plate connected (MPC) joints for Chinese larch (Larix gmelinii (Rupr.) Rupr.) were conducted in four orientations. Load-deflection curves were obtained for each MPC jointed specimen. Ultimate tension load, translation stiffness, stiffness at large slip, and failure modes for each specimen were obtained. A Foschi 3-parameter model was found to fit the load-deflection curves very well. Wood grain, and MPC length and loading directions had significant effects on elastic deformation and stiffness at large slip of the MPC joints. Load parallel to the grain with MPC length parallel to load (AA) represented the highest elastic deformation, while load perpendicular to the grain and MPC parallel to load (AE) showed the lowest. Load perpendicular to grain with MPC length perpendicular to load (EE) presented the highest stiffness at large slip, AA the second, load parallel to grain-MPC length perpendicular to load (EA) the third, and AE the lowest. The translation stiffness and tension load showed similar trends in terms of the effect of test orientations. The ultimate tension load was reduced by 18.9% from AA to EA, 34.2% from AA to AE, and 36.8% from AA to EE. Multiple failure modes occurred at the MPC joint, including MPC shear failure, tooth withdrawal, and wood failure.

Estimation of ultimate tension load of methylmethacrylate bonded steel rods into concrete

This paper introduces an alternative method of predicting ultimate tension load of methylmethacrylate (MMA) bonded steel rods into concrete. In general, the elastic model is found to predict many of the major experimentally observed characteristics of adhesively bonded steel rods. This theory gives quite reasonable results when applied to epoxy adhesives, but does not agree with data of MMA adhesives. It is necessary, therefore, to modify the analysis in order to bring the elastic model into agreement with test data. This is done by assuming that c, which is a parameter in the analysis, is a function of the shear strain. The solution based on this concept leads to a more general equation which includes as a special case the elastic model previously used to represent the dependence of ultimate tension load on the bond length. Experimental evidence appears to indicate that the ultimate tension load of a MMA bonded steel rod can be predicted, to a good approximation, using this model.

Modified cruciate suture technique for arthroscopic meniscal repair: a technical note

Arthroscopic meniscal repair is the procedure of choice whenever a reparable tear is diagnosed. The cruciate suture for arthroscopic meniscal repair is a type of the outside-in technique. It has advantages like: (1) its ultimate tension load (UTL) is 1.6 times higher than the UTL of the vertical suture (gold standard), (2) it holds the circumferential collagen fibers of the meniscus in a three-dimensional plane compared to the vertical and horizontal sutures which hold the circumferential fibers of the meniscus in a two-dimensional plane, (3) simple instrumentation, (4) could withstand not only distraction forces on the repaired meniscal tear but also, shear forces because of the oblique orientation of the cruciate suture limbs. It has disadvantages like: being difficult to perform and time-consuming. A modified technique is presented in this study which has the following advantages; (1) less time-consuming, (2) performed through a smaller skin incision, (3) a sliding knot is used to tie the cruciate suture.

The “Cruciate Suture” for Arthroscopic Meniscal Repair: A New Technique

Meniscal repair has become the treatment of choice whenever a reparable tear is diagnosed. Fixation strength of the repair technique is always of paramount importance in comparison of various techniques, especially after the evolution of many arthroscopic all-inside devices. We present a new arthroscopic meniscal repair suturing technique called “cruciate suture.” One 18-gauge needle and suture material are used. The needle is loaded with the suture material from its tip. The suture is folded at the tip of the needle, which is inserted to penetrate the skin obliquely to appear inside the joint, making a loop. The needle is retracted, while the suture is kept inside of it. The needle is reinserted at the same hole, appearing inside the joint and making a second loop. The needle is retracted completely. With the use of a probe, the loop at the second point is pulled through the loop at the first point, thereby forming a free end. The 2 limbs of the loop are pulled, thus driving the limb with the free end outside of the joint. The first oblique vertical suture is completed at this point. The needle is reloaded by the suture limb from the first point. The previous procedure is repeated, with use of the second skin hole and the third and fourth points to make the second oblique vertical suture. The cruciate suture is now complete. We tested the ultimate tension load (UTL) of the cruciate suture in comparison with that of the vertical suture (the gold standard). A total of 36 tests (18 for the cruciate suture and 18 for the vertical suture) were performed on human menisci. The mean UTL of the cruciate suture was measured at 110 N; the mean UTL of the vertical suture was 67 N.

Biomechanical investigations of different meniscal repair implants in comparison with horizontal sutures on human meniscus

Purpose: The use of biodegradable implants for arthroscopic repair of meniscal lesions is becoming increasingly popular. The aim of this study was to test the biomechanical stability and the mode of failure of these implants. Type of Study: Biomechanical testing study. Methods: Biomechanical investigations were performed on human menisci using 6 commonly used biodegradable implants for meniscal repair to compare them with horizontal mattress suture using 2/0 Ethibond (Ethicon, Norderstedt, Germany). Included in this study were the Meniscus Arrow (Bionx, Tampere, Finland), Dart (Arthrex, Naples, FL), Stinger (Linvatec, Largo, FL), Meniscal Screw (Innovasive, Marlborough, MA), T-Fix (Acufex, Mansfield, MA), and the Fastener (Mitek, Westwood, MA). The tests were carried out using a material testing machine at a loading rate of 10 N/second. The ultimate tension load (UTL), elongation, and stiffness were evaluated for each implant technique. Results: The highest UTL was shown by Ethibond (62 ± 7.91 N) and the T-Fix (51.35 ± 16.31 N), followed by the Fastener (32.67 ± 2.97 N). All other implants had a significantly lower UTL (P =.001). Less elongation under a load of 5 N was noted for Ethibond (0.64 ± 0.25 mm) and for T-Fix (0.43 ± 0.32 mm) compared with the other implants. The greatest elongation was found for the Fastener (2.239 ± 0.581 mm). The stiffness of the fixation was similar in all implants, except for the Dart and Fastener, which were significantly inferior (P <.05). Conclusions: All of the biodegradable implants had lower UTL than the suture techniques. Therefore, when using the implants, they should be inserted close together to provide sufficient stability. In cases of an extended lesion, there might even be an option to combine the implant and suturing techniques.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 5 (May-June), 2001: pp 439–444

Mechanische Eigenschaften von Fadenmaterialien zur Verankerung von Kreuzbandtransplantaten

The fixation of hamstring grafts in ACL reconstruction requires a connector device. During the process of ingrowing the graft stability depends entirely on the fixation. The following study focused on the mechanical conditions of no 6 Ethibond, 5 mm Mersilene tape and 5 mm Polylene tape. The material were tested as loops with a length of 30 mm including the knot similar to intraoperative conditions. The ultimate tension load and elongation of the conditioned and unconditioned loops were investigated under cyclic load of 50 N and 100 N using a tension load machine. The ultimate tension load increased significantly only for Mersilene from 416 N to 462 N. However, the highest ultimate tension load showed Polylene with 479 N. The oscillating load up to 100 N revealed for unconditioned loops an elongation of 4.1 mm for Ethibond, 2.9 mm for Polylene and 5.4 mm for Mersilene. The elongation decreased significantly for the conditioned loops to a maximum of 1.4 mm. Concerning the amplitude during the period of oscillating load there was found a significant reduction as well. Based on our results Polylene showed the best mechanical properties. Regardless the intraoperatively used material we advocate the conditioning of the loops before anchoring the hamstring graft in ACL reconstruction.

Axial Decay of Self-Equilibrating End Loads in Compressible Solids

The axial diffusion rate of self-equilibrating surface loads is investigated for axially prestretched solids under plane-strain conditions. The perturbed field within the body, induced by an instantaneous end disturbance, is examined by using the eigenfunction spectral analysis. A general solution is given for a wide range of compressible materials. Particular examples are presented for a few hyperelastic solids. Very slow rate of decay, of the first antisymmetric eigencomponent, has been found near the stress-free configuration. Also, there is almost no decay of the first symmetric eigencomponent near the ultimate tension load. The diffusion length is greater for less compressible solids. Axial decay is exponential and depends quite strongly on material moduli and prestrain.