Design of Partially or Fully Composite Beams, with Ribbed Metal Deck, Using LRFD Specifications
A Hindu saying states, "One picture is worth a thousand words (numbers)." With this optic in mind, the design aspects of steel-concrete composite beams using the recently adopted LRFD specifications 1 are analyzed critically and the significance of several parameters is brought out clearly. Charts are then constructed to facilitate the design of partially or fully composite beams using rolled-steel, wideflange sections of A36 steel or A572 Gr. 50 steel. The slab may be a composite metal deck slab with ribs perpendicular to the beam, a haunched slab or, simply, a flat soffit concrete slab. The charts cover both adequate and inadequate slabs. The charts provided are a valuable tool from the practical standpoint, and also familiarity with them should contribute to the student's and young engineer's overall feel of the composite beam design problem. The design charts given here complement the composite beam design tables provided in the LRFD manual.
Design charts for flat soffit, fully composite beams using LRFD specifications
Presentation de tables graphiques pour le dimensionnement de poutres mixtes composees d'une poutre en acier et d'une dalle rectangulaire en beton, incluant les parametres pour le calcul des connecteurs, selon les nouvelles regles AISC («Load and resistance factor design»)
Heavy metal adsorption from industrial wastewater by PAMAM/TiO2 nanohybrid: Preparation, characterization and adsorption studies
Abstract This study investigates the removal of heavy metals from industrial wastewater using TiO 2 nanoparticles modified with poly-amidoamine dendrimer (PAMAM, G 4 ). The metal ions Cu 2 + , Pb 2 + , and Cd 2 + were selected as model pollutants. FTIR, SEM, BET surface area and Zeta potential measurements, and Dispersion Observing methods have been employed for characterizing the synthetic nanohybrid and these techniques indicated that the PAMAM loaded on to TiO 2 have been favorably synthesized. The effects of several parameters including initial metal ion concentration, temperature, pH solution, the nanohybrid dosage and contact time were studied. The experimental data were analyzed using equilibrium isotherm and kinetics models. The adsorption process was studied using isotherm, kinetics, and thermodynamics models. The analysis shows that the Langmuir isotherm and pseudo-second-order kinetics are appropriate models for the adsorption process. The thermodynamic parameters illustrate that the absorption is endothermic and spontaneous. The findings suggest that the nanohybrid is a good super absorbent for the removal of heavy metals from industrial effluents.