Global structural analysis of central cores supported tall buildings compared with FEM
The focus of this article is to present an approximate method of calculation based on the equivalent column theory. This approximate method of calculation may be successfully applied in the case of tall buildings. Knowing the geometrical and stiffness characteristics of the structure, applying the equivalent column theory may determined: the displacements in both directions, the rotation of the structure, critical load, shear forces, bending moments for each resisting element and the torsional moment of the structure. The results obtained using the approximate calculation method will be compared with the results obtained using an exact calculation based on F.E.M.: Autodesk Robot Structural Analysis and ANSYS 12.1.
Determination of load transfer in reinforced concrete solid slabs by finite element computer analysis
According to the ACI building code, the concrete slab can be divided into two types depending on the ratio of the long side to the short side. Regarding the results of the ratio, the concrete slab can be divided as one-way and two-way slabs. The main objective of this paper is to study the stress or moments distribution in solid slab panel in its two directions and compare with ACI code assumption that the load is transferred mainly in short direction and most of the load is transferred in one direction only if the ratio of the longer span to the shorter span is greater than one. This will be discussed by analyzing one panel of solid slab using the computer software SAP2000. Two types of panels will be used; the first one a panel that is supported simply on its four sides and the second panel is supported only by four pin supports and beams. This paper shows that the gravity load on the slab is transferred to long and short direction. This means that one-way concrete solid slab doesn't exist and all concrete solid slabs work as a two-way concrete slab.
Simplified impedance design and control for low-cost high-speed channels
Impedance design is the fundamentals of signal integrity at the very beginning, but controlled impedance is always costly or time-consuming for the high-speed channels. In this paper, many simulations of channel parasitics were taken and calculated that met with the specified impedances and correlated to the measurements very well. Selection of the different substrate stack-up without any layout modification in the BGA package reversed from the failed verification to pass the differential return loss. Adjustment of lead widths and spaces in the limited room of leadframe package improved 6 Ω of differential-mode impedance compared to the conventional leadframe packages. The differential pairs with wider traces routed on the 2-layer PCB are more robust for over-etching effects whose impedance errors are less than 5% without special impedance control. Moreover, those pairs inserted with a thin ground trace achieved 90 Ω differential-mode impedance and 28.2 Ω common-mode impedance simultaneously with 35% less routing area for MHL application and reserved a 10 Ω series resistor for ESD protection. With those diligent designs, the leadframe package and the 2-layer PCB can be still adopting in the consumer electronics for high-speed applications.