Number Of Nails Research Articles

Reliability of nailed timber connections with gusset plates

First order second moment (FOSM) analysis techniques, recently employed in the development of limit states design codes allow the engineer/designer to take into account the variations and random nature of the material properties and load effects present in the design of structural timber. A generated non-linear equation is used in conjunction with basic design mechanics to model the moment–rotation behaviour of dowel type (nailed) timber connections. The connections examined incorporated a series of nailed gusset beam to column joints with varying number of nails, subjected to a series of permanent and variable loading conditions. Joint reliability is evaluated by imposing an end rotation and calculating the reliability index under imposed deformation levels. The parameters of the equation considered as random variables were nail diameter, timber density, connection geometry and the applied loading condition. The statistics of the random variables considered are modelled using the normal, lognormal and extreme value type-1 (Gumbel) distributions. Results show that irrespective of the magnitude of variation of the other parameters, nail diameter significantly influences the moment-capacity of the connection, especially for smaller diameters. Use of probabilistic analysis techniques in design is intended to provide improved insight into system behaviour, the influence of different random variables on system performance and the interaction between different system components. This paper demonstrates how the incorporation of FOSM analysis with a non-linear moment–rotation model provides a more rational description of connection behaviour without the need to resort to more traditional Monte Carlo simulation, which can be both costly and time consuming.

The effects of hammer design and hammering surface orientation on task performance

This study examined the effect of hammer design parameters on task performance, operator physiological responses, perceived rate of exertion, task completion time, task accuracy, and user preference for hammering in the vertical (wall) and horizontal (bench) surface orientations. Two hammers used in the study differed with respect to their weight and softness of the handle grip. Ten male subjects participated in the laboratory experiment. The results showed that hammer design differences affect hammering task performance and perceived physical exertion. In general, the horizontally-oriented hammering task was faster than vertically-oriented hammering. However, task accuracy (i.e. number of nails hammered straight) was not statistically different with respect to either hammering orientation or hammer design. Subjects identified handle design, weight, and hammer mass distribution as critical factors that affect hammering task performance.

Nailed Tubular Connections under Fatigue Loading

Tests on nailed connections under static axial tension or compression loading have resulted in published limit-states design procedures for these types of splice connections. This paper presents the results of an experimental study on the fatigue behavior and performance of similar nailed tubular connections. An example of this is nailing light gauge steel diaphragms to primary structural members in German railway bridges to provide acoustic damping properties. A total of 24 lapped splice nailed tubular connections has been tested with variables including tube thickness, number of nails, and stress range. Five of these connections were tested under static loading to serve as a benchmark for the fatigue test series. The fatigue test series consisted of 19 specimens tested under constant amplitude fatigue loading. The performance of nailed tubular connections has consistently proven to be reliable and predictable under static and, now, fatigue loading conditions. As such, design criteria for nailed connections can be included in structural steel design specifications.

Effect of interface gap on load–slip characteristics of timber joints fabricated with multiple nails

An experimental program, exploratory in nature, has been carried out to investigate the effect of interface gap on the load–slip behaviour of joints fabricated with multiple nails. In total, 320 joint specimens have been tested. Modification factors are developed to account for the effects of number of nails and interface gap on the overall load-carrying capacity of joints with multiple nails. The current practice for the design of nailed joints is that a joint fastened together with multiple nails in a row, regardless of the interface characteristics of that joint, carries lateral load equal to the product of the lateral-load capacity of the corresponding joint with a single nail and the number of nails in a row of the joint. The findings of this investigation indicate this practice to be somewhat of an overestimation of the overall capacity of the joint. Key words: design, interface gap, interface friction, joint slip, loads (forces), modification factors, multiple fasteners, nailed joints, stiffness, structural engineering, tests, timber construction.

Ender nailing for peritrochanteric fractures of the femur. An analysis of indications, factors related to mechanical failure, and postoperative results.

Of 100 patients with a peritrochanteric fracture of the femur treated by the Ender technique, we reviewed the cases of seventy-nine after an average follow-up of 11.4 months in order to clarify the indications for the procedure and investigate variables that may affect the results. The variables that correlated with the failure rate appeared to be the quality of the reduction, the number of nails used, the experience of the surgeon with the technique, and the degree of fracture instability. Nail placement in terms of medial-lateral and anterior-posterior positioning within the femoral head, however, did not appear to correlate. The Ender technique seems to be reasonably effective both for the treatment of stable intertrochanteric fractures and, if a good reduction and four or more nails are used, for the treatment of four-part unstable fractures. We do not recommend the technique for fractures with a subtrochanteric component unless mobilization of the patient can be delayed.

Ender nailing of pertrochanteric fractures: Complications related to technical failures and bone quality

In a series of 127 consecutive patients with trochanteric femoral fractures treated with Ender nailing, bone quality and technical failures were analysed. Of the fractures, 35 per cent were stable and 65 per cent unstable according to the definitions of Evans. There were no implant failures. Technical failures occurred in 16 cases. These could be referred to unsuitable location of the nails in the femoral head and/or to an insufficient fixation of the nails in the medullary cavity, especially in patients with poor bone quality and unstable fractures. Technical failures should therefore be preventable. When a correct surgical technique is used with a sufficient number of nails in femurs with low bone quality and a wide medullary canal, the method seems to be a simple and safe treatment for most pertrochanteric fractures, with elimination of many of the problems often associated with this injury.

Treatment of onychomycosis by partial nail avulsion and topical miconazole.

13 patients with distal subungual onychomycosis in a total of 48 dermatophyte-infected nails were treated with chemomechanical, partial nail avulsion followed by topical miconazole for 8 weeks. On examination, 6 months after cessation of therapy, 42% of the nails were cured by clinical and mycological criteria. The therapeutic response was related to the pretreatment extension of subungual hyperkeratosis. Periungual skin irritation was common during the initial avulsion period. Miconazole solution was well tolerated and this treatment modality proved to be a valuable alternative to other remedies for the treatment of onychomycosis limited to a few number of nails.

Analysis and Design of Griplam Nailed Connections

A stress analysis for Griplam nailed connections is presented for loads parallel and loads perpendicular to the grain. For loads parallel to the grain, two modes of failure are studied: (1)Yielding of the nails in bending with simultaneous bearing failure of the wood under the nail shanks; and (2)wood failure around the group of nails. Maximum stresses in the wood are determined in terms of geometrical parameters of the connection: number of rows of nails, number of nails per row, nail penetration length, spacing of nails, and distances between the nail group and edges of the timber member. Ultimate loads are derived for both modes of failure and allowable loads are determined. For the second mode, Weibull's theory of brittle fracture applied to the longitudinal shear strength of wood is used. Good agreement is shown between theoretical failure loads and full-size connection test results using Douglas-fir. Design procedures are proposed.

Om Barbartemplets datering

Om Barbartemplets datering

Removal of Large Numbers of Nails, Etc., from the Stomach by Gastrotomy—Recovery

Removal of Large Numbers of Nails, Etc., from the Stomach by Gastrotomy—Recovery

Greek Cross: Number of Nails

Greek Cross: Number of Nails