Plate Test Results Research Articles

BASIC COMPRESSIVE STRENGTH OF STEEL PLATES FROM TEST DATA

This paper describes a data-base approach to the ultimate compressive strength of unstiffened plates loaded in uniaxial compression. A total 793 individual test results of plates is surveyed and stored into the Numerical Data-Base for the Ultimate Strength of Steel Structures (NDSS). Statistical assessments are made for the plate test results to compare with the available strength formulas. And the effects of initial imperfections such as residual stress and initial out-of-flatness are discussed. Then strength formulas are proposed for two groups, “with residual stress” and “without residual stress”. to explain more accurately the test data.

Relationship Between Phase Difference and Coefficient of Restitution During Low Velocity Foreign Object Transverse Damage of Composite Plates

This work discusses a model to correlate the coefficient of restitution of low velocity transverse impacts of graphite-epoxy laminates with the residual deformation or central deflection at the end of the impact event. It is assumed that the energy absorbed by the target can be calibrated in terms of residual deflection, and thereby in terms of phase difference between the occurrence of impact force and central deflection to their maximas. Analysis was modeled on the basis of the experience from impact tests. Predictions are compared with the test results of impacted circular and flat plates. Experimentally measured values of coefficient of restitution and phase difference agreed well with the predicted relationship between them.

The hair-dye reagent 2-(2′,4′-diaminophenoxy)ethanol is mutagenic to Salmonella typhimurium

A new hair-dye ingredient, 2-(2′,4′-diaminophenoxy)ethanol (2,4-DAPE), was described as being devoid of any genotoxic activity on the basis of a multi-laboratory study. Since 2,4-DAPE is a close analogue of 2,4-diaminoanisole (2,4-DAA), which is mutagenic and carcinogenic, we tested this claim by assaying 2,4-DAPE for bacterial mutagenicity. Two samples of 2,4-DAPE · 2HCl were synthesized by reduction of the corresponding dinitrophenoxyethanol and identity and purity were established by elemental analysis, NMR spectrometry, mass-spectrometry, UV-spectrophotometry, TLC and HPLC. Fresh aqueous solutions of 2,4-DAPE · 2HCl were assayed in several separate plate tests using S. typhimurium TA1538, TA97, TA98 and TA100, and E. coli WP2uvrA (pKM101), 3 plates per dose and 0%, 4%, 10% and 30% Aroclor 1254-induced rat-liver S9 in S9 mixes. We obtained negative results in TA100 and E. coli. Reproducible, statistically significant dose-related increases in revertants (up to 14 times the background) were obtained in frame-shift mutants of S. typhimurium in the dose range 10–80 μg per plate. Mutagenicity was S9-dependent, significant increases in revertants being obtained only with 50 μl per plate or more of S9. 2,4-DAPE induced significant mutagenic effects at doses of < 1 μg per ml in TA1538 and TA98 in fluctuation tests using 2% S9 in the S9 mix. In plate tests, 2,4-DAPE was less mutagenic (by a factor of about 8) than 2,4-DAA, which gave the highest mutant yields with 20 μl S9 per plate (4% S9 in the S9 mix). 2,4-DAPE obtained commercially was about 8 times more mutagenic than our sample of 2,4-DAPE. After purification, the commercial product, now chromatographically identical with our own sample, gave plate-test results close to those obtained for our samples of 2,4-DAPE. A review of the published reports (in which 2,4-DAPE was claimed to be inactive in a variety of short-term tests) revealed: (a) the use of protocols for bacterial mutagenicity testing which, in the light of our own results, were probably too limited in scope, especially in the choice of conditions for metabolic activation; (b) insufficient information on the identification and purity of the samples of 2,4-DAPE tested in the published collaborative study.

Relationship between compression moduli of soils obtained from the results of dynamometer and plate tests

Relationship between compression moduli of soils obtained from the results of dynamometer and plate tests

Screw plate tests in a stiff clay : Kay, J N; Parry, R H G Ground Engng, V15, N6, Sept 1982, P22–30

In carrying out a site investigation a number of techniques are available for use in the laboratory and in the field designed to measure soil strength and deformation properties. While the vane and cone penetrometer tests allow soil to be tested in a generally undisturbed state they provide only limited information. The self-boring pressuremeter has provided an instrument which, in suitable soils, can test essentially undisturbed soil and provide a range of soil parameters. A simpler test device described, also able to provide the same results, is the screw plate. This device has the added advantage that it loads the ground vertically which corresponds to the direction of loading associated with geotechnical problems. The article reviews methods of interpretation of test results and discusses results of screw plate tests carried out in stiff gault clay. (TRRL)

The effects of mutations in the polA and recA genes on mutagenesis by nitrosoguanidine in Salmonellatyphimurium

Results of semi-quantitative plate tests indicated that polA and recA mutants of Salmonella typhimurium strain LT2 trpB1 might be significantly less mutable by nitrosoguanidine (MNNG) than were their repair-proficient parents strains. Quantitative data obtained in treat-and-plate experiments showed that this was not the case, at least for low doses of MNNG, and also that the recA strain was significantly more mutable at low doses than its Rec + parent. On the basis of these results it is suggested that cells of S. typhimurium may possess a recA +-dependent repair pathway capable of error-free removal of MNNG-induced pre-mutational lesions from their DNA.

Screw plate testing of a soft clay

The screw plate test was developed for the determination of the in situ deformability characteristics of both granular and cohesive soils. This paper examines several theoretical models that may be used to evaluate the in situ undrained deformability and shearing strength characteristics of a cohesive soil medium from results of screw plate tests. It is shown that the undrained modulus and the undrained shearing strength can be evaluated directly from the load–displacement response obtained from the screw plate test.

Tests on piles in Keuper Marl for the foundations of a blast furnace at Redcar

One of the largest bIast furnaces in Europe is currently being constructed for the British Stee Corporation at Redcar, Teesside. The structure is supported by a 38 m square, 4·O m thick slab carried on 600 mm dia. endbearing piles in the Keuper Marl at a depth of 15 m. The site is on the estuary of the River Tees with a geology consisting of alluvium overlying the marl. The Paper discusses structural design requirements, site investigation and the character of the marl as revealed in boreholes at the site, results of plate tests carried out by the Building Research Establishment (BRE), preliminary pile load test results and their correlation with the plate tests and working pile tests, and construction problems. Assuming an elastic untform response from the pilehnarl system (pile/marl stifness, 180 MN/m per pile) a dished conjiguration was pre dicted for dejlexion of the slab with maximum settlement of 7 mm and d@erential defexion of 3 mm due to slab deformation. Cores ‘obtained from boreholes at the site exhibited all the weathering zones of the CIasstjication proposed by Skempton and Davis. Frequent reversals in degrees of weathering were encountered. Estimates of the in situ moduli of the marl obtained by the BRE from plate loading tests on 865 mm and 584 mm dia. plates range from about 50 MN/m2 in the highly weathered marl to upwards of 3000 MN/m2 in the unweathered marl. The values determinedfrom the piles founded immediately above the unweathered marl were higher than the in situ values determinedfrom the plate tests in the weathered marl, reflecting the effects of com paction during formation of the piles. Un des plus importants hauts fourneaux d'Europe est actuellement en train d'être construit pour la British Steel Corporation à Redcar, Teesside. La structure est supportée par un radier careé de 38 m, de côté et d'une épaisseur de 4·0 m implante’ sur des pieux de 600 mm travillant en pointe dans le marne du Keuper à une profondeur de 15 m. Le chantier est implanté sur l'estuaire de la rivière Tees dont la géologic consiste en un dépôt alluvionnaire surmontant la marne. La communication discute les prescriptions du projet de structure, la reconnaissance des sols et les caractéistiques de la marne telle qu'elle a été révélée dans les trous de sondage sur le chantier, les résultats des essais de plaque entrepris par le Building Research Establishment (BRE), les résultats préliminaires d'essai de chargement de pieu et leur corrélation avec Ies essais de plaque et Ies essais de pieu réel, et les problèmes de construction. Admettant une réaction élastique uniforme du système pieu-marne (raideur pieu-marne, de 180 MN/m par pieu) une déformation plane a été prédite pour l'aflaissement du radier avec un tassement maximum de 7 mm et un tassement différentiel de 3 mm causé du radier. Les échantillons obtenus dans les sondages sur le chantier, ont montrés toutes les zones d'altération de la classification proposée par Skempton et Davis. Des changements fréquents du degré d'altération furent rencontés. Les estimations du module in situ de la marne obtenues par le BRE avec des essais de chargement sur des plaques de 865 mm et 584 mm ont varié d'environ 50 MN/m2 dans la marne à altération importante jusqu'au-dessus de 3000 MN/m2 dans la marne intacte. Les valeurs déterminées avec des pieux fondés au-dessus de la marne intacte étaient plus élevées que les valeurs in situ déterminées par des essais de plaque dans la marne altérée, reflétant les eflets de compactage pendant la réalisation des pieux.

POST-TENSIONED FLAT PLATE TO COLUMN CONNECTION BEHAVIOR

Three post-tensioned flat plate specimens (9 ft square) with a single column stub in the center and reinforced with various amounts of bonded reinforcement were loaded to failure. Test data were obtained on shear capacity, flexural strength, and general behavior in the column connection area. The results were compared with the current ACI Building Code (318-71) design equations and previous flat plate test results. The supplementary bonded reinforcement enhanced overall behavior providing crack control and increasing shear and flexural strength. This study represents only the first phase of a continuing research program on post-tensioned flat slabs. The results of the two later nine-panel model tests will be reported upon in the near future.