Chinese GB Research Articles

Sustainable Thermal Comfort by Age Group in Shopping Malls: Multi-Year Winter Surveys in a Severely Cold Region

The current Chinese standard utilizes a single thermal comfort index guide to regulate indoor parameters for public buildings. However, heating, ventilation, and air conditioning (HVAC) settings often do not align with the occupant’s needs. To address this, a 2-year winter field survey was conducted in four large-scale shopping malls across severely cold regions of China, considering the complex age structure of mall visitors. Physical environmental parameters were measured, and a subjective questionnaire yielded 1464 valid responses. Neutral temperatures for different age groups were 17.4 °C for children (0–12 years of age), 19.3 °C for early youth (13–24), 20.0 °C for mature youth (25–44), and 23.3 °C for middle-aged adults (45–59). The limit of the 80% acceptable temperature range for the children and early youth was lower than the current Chinese GB 50736 standard, suggesting that HVAC temperatures for the corresponding shopping malls can be appropriately reduced for the target consumer groups. Significant differences occurred between customers’ demand for thermal environments in shopping malls and various standards. These findings provide valuable insights into energy-efficient architectural design and operational management of shopping malls in the Shenyang area, promoting the sustainable development of human thermal comfort environments.

Numerical investigations of fire-resistant steel welded I-section columns under elevated temperatures

Based on the experimental investigations on compressive buckling behavior of fire-resistant steel columns subjected to elevated temperatures, the numerical analysis models were established and validated by the experimental results of 12 fire-resistant steel columns and 15 conventional steel columns. The parametric analysis was performed to examine the influence of cross-section types, axial load ratios, normalized slenderness ratios, initial imperfections, residual stress and temperature elevation procedure on critical temperatures of fire-resistant steel columns. The parametric analysis indicated that: (1) The critical temperatures increased with decreasing axial load ratios and slenderness ratios; (2) The fire resistance of column with higher axial load ratios and middle slenderness ratios were more sensitive to the residual stress and initial imperfections; (3) Cross-section size and temperature elevation curve variations had less influence on critical temperatures. Furthermore, a total of 1674 numerical simulations were compared with the results determined from the current standards. It was found that provisions in Chinese GB 51249 and European EC 3 tended to overestimate the compressive buckling coefficient while underestimate the critical temperature, when applied to fire-resistant steel columns. Based on Perry-Robertson formula and EC 3 critical temperature formula, the fire resistance determination methods were proposed to facilitate the engineering application of the fire-resistant steel. The proposed methods were proved to meet both safety and economic requirements of structural design.

Behaviours of circular CFDST with stainless steel external tube: Slender columns and beams

In this work, experimental and numerical investigations were performed on the behaviours of circular concrete filled double steel tubular (CFDST) slender columns and beams, in which the external tube employed stainless steel tube. Eighteen specimens, 12 slender columns and 6 beams, were tested to obtain the failure patterns, load versus deflection relationships and strain developments of stainless steel tube. A finite element (FE) model was developed and verified by experimental results. The validated FE model was then employed to investigate the effects of key parameters, including hollow ratio, eccentric ratio and material strength, on the load-carrying capacity. The load distribution among the components and contact stress between steel tube and sandwiched concrete were also analyzed. Finally, the design methods for CFDST, hollow CFST and solid CFST members with carbon steel external tube respectively suggested by Han et al. (2018), Chinese GB 50936-2014 (2014) and AISC 360-16 (2016) were employed to evaluate their applicability for the circular CFDST slender columns and beams with stainless steel outer tube.

Development of Standards for Hydrogen Storage and Transportation

Hydrogen storage and transportation are the intermediate link of hydrogen production and the point of end-use. Standards for hydrogen storage and transportation published by ISO, CGA, NFPA, ASME, ANSI, SAC, CEN and JISC are reviewed and analysed in this paper. Numbers of standards for hydrogen embrittlement are more than the others. Standards for hydrogen piping and pipelines are only published by CGA and ASME. Chinese GB standards are mainly focused on general design and safety, gaseous hydrogen receptacles and hydrogen embrittlement. Standards for liquid hydrogen storage receptacles and safety, hydrogen piping and pipelines, and hydrogen transportation should be emphasized.

Improved design of special boundary elements for T-shaped reinforced concrete walls

This study examines the design provisions of the Chinese GB 50011-2010 code for seismic design of buildings for the special boundary elements of T-shaped reinforced concrete walls and proposes an improved design method. Comparison of the design provisions of the GB 50011-2010 code and those of the American code ACI 318-14 indicates a possible deficiency in the T-shaped wall design provisions in GB 50011-2010. A case study of a typical T-shaped wall designed in accordance with GB 50011-2010 also indicates the insufficient extent of the boundary element at the non-flange end and overly conservative design of the flange end boundary element. Improved designs for special boundary elements of T-shaped walls are developed using a displacement-based method. The proposed design formulas produce a longer boundary element at the non-flange end and a shorter boundary element at the flange end, relative to those of the GB 50011-2010 provisions. Extensive numerical analysis indicates that T-shaped walls designed using the proposed formulas develop inelastic drift of 0.01 for both cases of the flange in compression and in tension.

The Glass Phase Characterization of Coal Ash Slag

In recent years, coal power generation are strongly desired lower environmental burden, emissions of SOx, NOx, and CO2 are reduced to the level. Since high efficiency of combustion or gasification systems are discharges coal ash component of complex ashes or glassy molten slag(what is CCP), and the other point of view these CCPs are expected to be effectively used for sustainable development as component for civil engineering etc. Using the CCPs for civil engineering work, Pozzolanic reactions are very important character with hydration materials, but to measure Pozzolanic reaction by mortar test is necessary to wait very long term, waiting the new method of determine the Pozzolanic reactions. So, chemical and mineralogical investigations were carried out on these inorganic materials. The glass phase which was formed by quenching is difficult to characterize by X-ray analysis by every CCP, and discussed only how percentage of glass phases, without not good explanation of CCP reactions in each steps. So in this study, we promote the new method by optical analysis and acid extraction tests etc. In this study, three phases are distinguished, such as glass I, glass II, and crystal phase. Glass I has low flux compositions, and glass II has high flux compositions which makes the basic character of Class C ash in ASTM and Chinese GB standards.

THE VARIATION OF MINERAL PROFILES FROM GRAPE JUICE TO MONOVARIETAL CABERNET SAUVIGNON WINE IN THE VINIFICATION PROCESS

ABSTRACT The variation of mineral profiles in the vinification process was investigated in this paper. The concentrations of 10 mineral elements (Al, Cu, Fe, Zn, Mn, Ca, K, Mg, Na and Sr) in grape juice, must and wine were analyzed by inductively coupled plasma optical emission spectrometry. Cabernet Sauvignon grapes from two districts, Yinchuan and Changli, were used in two vinification batches, respectively. The results indicated that there were significant differences (P < 0.01) of the contents of each element among individual vinification steps for two batches. The content of Fe in the batch used grapes from Yinchuan was 6.66 mg/L, which was close to the maximum level of 8 mg/L in Chinese GB 15037-2006. Some measures should be taken in practice to control contamination. In addition, strong correlations (P < 0.01) of the mineral profiles between the wines and origin grapes were observed in both batches. The profile of the 10 mineral elements in a wine can be tentatively used as a fingerprint to distinguish one wine origin from another. PRACTICAL APPLICATIONS This study will lay the foundations for hazard analysis and critical control point (HACCP). The results will guide the winery to control and enhance the quality of the wine. In addition, a mineral profile of a wine was potentially taken as the fingerprint of the wine origin.

Synthesis of accelerograms compatible with the Chinese GB 50011-2001 design spectrum via harmonic wavelets: artificial and historic records

A versatile approach is employed to generate artificial accelerograms which satisfy the compatibility criteria prescribed by the Chinese aseismic code provisions GB 50011-2001. In particular, a frequency dependent peak factor derived by means of appropriate Monte Carlo analyses is introduced to relate the GB 50011-2001 design spectrum to a parametrically defined evolutionary power spectrum (EPS). Special attention is given to the definition of the frequency content of the EPS in order to accommodate the mathematical form of the aforementioned design spectrum. Further, a one-to-one relationship is established between the parameter controlling the time-varying intensity of the EPS and the effective strong ground motion duration. Subsequently, an efficient auto-regressive moving-average (ARMA) filtering technique is utilized to generate ensembles of non-stationary artificial accelerograms whose average response spectrum is in a close agreement with the considered design spectrum. Furthermore, a harmonic wavelet based iterative scheme is adopted to modify these artificial signals so that a close matching of the signals’ response spectra with the GB 50011-2001 design spectrum is achieved on an individual basis. This is also done for field recorded accelerograms pertaining to the May, 2008 Wenchuan seismic event. In the process, zero-phase high-pass filtering is performed to accomplish proper baseline correction of the acquired spectrum compatible artificial and field accelerograms. Numerical results are given in a tabulated format to expedite their use in practice.

Larix gmelini tannin-based adhesive for plywood

Larix tannin-phenol-formaldehyde (TPF) adhesive, having 60% by weight of phenol being replaced, was evaluated for its utilization in plywood. The kinetic characteristic of the TPF resin was investigated through differential scanning calorimetry (DSC) and the results obtained from the DSC scans show that the resin has a little bit different thermochemical behavior from that of phenol-formaldehyde (PF) resin. Two kinds of plywood panels were produced using the TPF adhesive in laboratory. The desired test results met the Chinese GB 9846-88 and ZB B70006-88, respectively, and the long assembly time of TPF resin in preparing plywood can be improved by mixing with the filler.All the properties of plywoods bonded with the TPF adhesive were compared with those obtained with synthetic PF adhesive.