Behavior of axially loaded circular stainless steel tube confined concrete stub columns

A stainless steel tube confined concrete (SSTCC) stub column is a new form of steel-concrete composite column in which the stainless steel tube without bearing the axial load directly is used to confine the core concrete. It could take the advantages of both the stainless steel tube and the confined concrete columns. This paper presents the experimental investigation of circular SSTCC stub columns subjected to axial load. Meanwhile, comparative tests of the circular concrete-filled stainless steel tubes and circular hollow stainless steel tubes were also conducted. The experimental phenomena of specimens are introduced in detail and the experimental results are analyzed. Through the investigation of axial stress and circumference stress on the stainless steel tube, the interaction behavior between stainless steel tube and core concrete is studied. The experimental results showed that the stainless steel tube provides better confinement to the concrete core, thus results the compressive capacity increased obviously comparing with unconfined concrete. The load-carrying capacity of SSTCC stub columns is higher than that of concrete-filled stainless steel tubes. An equation to calculate the load-carrying capacity of SSTCC stub columns was proposed, the results based on calculation are close to the experimental results

Bulk matter fields on two-field thick branes

In this paper we obtain a new solution of a brane made up of a scalar field coupled to a dilaton. There is a unique parameter $b$ in the solution, which decides the distribution of the energy density and will effect the localization of bulk matter fields. For free vector fields, we find that the zero mode can be localized on the brane. And for vector fields coupled with the dilaton via $\text{e}^{\tau\pi}F_{MN}F^{MN}$, the condition for localizing the zero mode is $\tau\geq-\sqrt{b/3}$ with $0-1/\sqrt{3b}$ with $b>1$, which includes the case $\tau=0$. While the zero mode for free Kalb-Ramond fields can not be localized on the brane, if only we introduce a coupling between the Kalb-Ramond fields and the dilaton via $\text{e}^{\zeta \pi}H_{MNL}H^{MNL}$. When the coupling constant satisfies $\zeta>1/\sqrt{3b}$ with $b\geq1$ or $\zeta>\frac{2-b}{\sqrt{3b}}$ with $0<b<1$, the zero mode for the KR fields can be localized on the brane. For spin half fermion fields, we consider the coupling $\eta\bar{\Psi}\text{e}^{\lambda \pi}\phi\Psi$ between the fermions and the background scalars with positive Yukawa coupling $\eta$. The effective potentials for both chiral fermions have three types of shapes decided by the relation between the dilaton-fermion coupling constant $\lambda$ and the parameter $b$. For $\lambda\leq-1/\sqrt{3b}$, the zero mode of left-chiral fermion can be localized on the brane. While for $\lambda>-1/\sqrt{3b}$ with $b>1$ or $-1/\sqrt{3b}<\lambda<-\sqrt{b/3}$ with $0<b\leq1$, the zero mode for left-chiral fermion also can be localized.Comment: 22 pages, 8 figures, improved version, accepted by Physical Review

Gravity Localization and Effective Newtonian Potential for Bent Thick Branes

In this letter, we first investigate the gravity localization and mass spectrum of gravity KK modes on de Sitter and Anti-de Sitter thick branes. Then, the effective Newtonian gravitational potentials for these bent branes are discussed by the two typical examples. The corrections of the Newtonian potential turns out to be $\Delta U(r)\sim 1/r^{2}$ at small $r$ for both cases. These corrections are very different from that of the Randall-Sundrum brane model $\Delta U(r)\sim 1/r^{3}$.Comment: 6 pages, 2 figure