Search results

Unbraced one-bay composite frames are an interesting load-bearing structure for buildings with up to three storeys. However, their fire design is demanding given the lack of simplified design methods. This paper aims to deepen the understanding of the load-bearing behaviour of both unbraced and braced frames when exposed to fire.

In a previous paper, a numerical model for the fire design of these frames was established and validated with good agreement against fire tests. In the current paper, this model was used to compare the typical differences between braced, semi-braced and unbraced composite frames under fire conditions. Further studies addressed the effect of different heating regimes, i.e. partial fire exposure of the columns in the frames and varying location of the ISO standard fire.

Numerical investigations showed that it is necessary to take local failure and deformation limits of the fire-exposed frames into account. On this basis, unbraced composite frames can compete with braced frames as they have to endure less thermal restraints than braced frames.

In contrast to other investigations on frames, the numerical model is able to take into account the shear failure, which is especially important within the frame corners. Using this model, it is shown that limited sway is reasonable to reduce thermal restraints and hence local stresses. In this regard, the concept of semi-rigid composite joints with a distinct amount of reinforcement has proven to be very rational in fire design.

The purpose of this study is to gain a deeper understanding of the structural behaviour of fire-exposed unbraced composite frames. Designers to date paid little attention to unbraced one-bay composite frames as structural system. There are two main reasons for this. First, codes lack simplified methods for the fire design of these frames due to their sway and the linked P-Δ effects when subjected to fire, which complicates the design. Second, it is demanding to construct external composite joints for the regarded one-bay frames. Thus, external joints in composite constructions are mostly constructed as steel joints. Nevertheless, these frames offer advantages. These include increased usable space and flexibility in the building’s use, large spans, fast construction times and inherent fire resistance.

To profit from these benefits, two different external semi-rigid composite joint were developed for the considered one-bay composite frames. The first solution based on concrete-filled steel tube columns and the second on concrete-filled double skin tube columns. Furthermore, a numerical model was established to study the fire performance of unbraced composite frames. The model was validated against four fire tests on isolated composite joints and two large-scale fire tests on unbraced composite frames.

Overall, the predictions of the numerical model were in good agreement with the test results. Thus, the numerical model is appropriate for further investigations on the fire performance of unbraced composite frames.

The sequence of construction results in significant stresses in the steel section, which creates difficulties in numerical modelling and may account for the relatively few studies carried out at room temperature. For the fire design, there was, to the best knowledge of the author, to date no numerical model available that was capable of considering the sequence of construction.

This paper aims to answer two questions. First, are there any differences in the fire performance of columns made of normal and of high-strength concrete? Second, under which circumstances does the fire design govern the cross-sectional dimensions of concrete columns? Is it feasible to replace columns out of normal strength concrete by more slender high-strength concrete columns?

The author conducted numerical studies using the finite element code “Infocad” of the German company “Infograph”. The studies included the effect of different parameters on the fire performance of columns out of normal and high-strength concrete, i.e. the load ratio and eccentricity, boundary conditions and times of fire exposure.

Results from the numerical investigations showed that high-strength concrete columns suffer much more from heating than normal strength concrete columns. This is the outcome of the unfavourable mechanical properties of high-strength concrete at elevated temperatures. Although the relative fire performance of columns out of high-strength concrete is worse than that of columns out of normal strength concrete, initial load reserves are beneficial to achieve even high fire ratings.

Many researchers addressed in experimental and numerical studies the fire performance of columns out of normal and high-strength concrete. A special emphasis was often laid on the spalling of fire-exposed high-strength concrete. However, there are no systematic investigations when the fire design governs the cross-sectional dimensions of high-strength concrete columns. Based on a previous comparison of the relative fire performance of columns out of normal and high-strength concrete, this paper, hence, addresses the question whether there is a reasonable lower limit for the use of these columns. This is an important aspect for designers since there is a tendency to replace columns out of normal strength concrete by columns out of high-strength concrete. Higher concrete strengths allow for smaller cross sections of the columns, and designers may, hence, increase the usable space of buildings.

In fire safety engineering, the ISO standard fire often represents fire action. Nevertheless, it is often not clear how conservative the ISO standard fire is when compared to natural fires. Thus, numerical research on fires in office buildings was conducted. To assess the severity of the ISO standard fire, the author proposes a simple approach basing on the heat release rate. For two regarded office rooms, artificial heat release curves were established and used as input in the zone model ‘Ozone’. These heat release curves were adjusted in order to match gas temperatures defined by the ISO standard fire. Integration of these curves allows for determining the total energy released by the fire. If this energy is related to the compartment area, it becomes possible to compare the ISO standard fire to natural fires. Results from the limited investigations show that the ISO standard fire becomes more conservative for longer fire duration and that it is quite realistic for offices with moderate opening factors and fire durations of 60 min at most. Contrary, the ISO standard fire tends to be very conservative for offices with higher opening factors.

The purpose of this paper is to empirically investigate the influencing factors of loan demand in agriculture. With the structural changes that agriculture is undergoing and the accordingly higher financing requirements and volumes, the analysis of loan demand in agriculture is of particular interest.

Detailed actual loan data at farm level, which is provided by a major German development bank for the agricultural sector, is used for the analysis. The data set covers the period from 2010 to 2014 and consists of 68,430 observations. Due to the data structure, an ordinary least square regression is conducted with the loan amount as the dependent variable. Many explanatory variables are included, such as the interest rate, the intended use of the loan, grace periods, the gross value added (GVA) and the business climate index for agriculture.

Amongst others, the authors find that interest rate, GVA, grace periods and farmers’ business expectations have significant effects on the loan demand in agriculture. According to the results, the interest rate has a significant negative effect, whereas the granted grace periods, the GVA in agriculture and farmers’ business expectations have significant positive effects on the loan demand.

This paper investigates the determinants of loan demand in agriculture in a developed country by using unique and comprehensive data at loan and farm level. Amongst others, elasticities of loan demand in agriculture are determined.

Agricultural-related food marketing claims are gaining in importance. The challenge for the industry is to claim real production characteristics while being in line with consumers’ expectations. Looking at the example of marketing pasture-raised milk year-round and the fact that cows only have access to pasture in summer, the purpose of this paper is to analyse consumer expectations, the potential of deception and the acceptance of more credible marketing strategies.

An online access panel was used for data collection. The data include 310 German milk buyers, who were grouped using cluster analysis to examine the different target groups for the year-round and seasonal marketing of pasture-raised milk.

The study distinguished two different consumer groups: one with lower expectations accepting year-round marketing (32.5 per cent) and the other with higher demands, who feel deceived by year-round marketing (46.7 per cent). Furthermore, one part of the last group is also sceptical towards the more precise seasonal marketing due to their general scepticism towards ag-related marketing claims.

To generate consumer trust in ag-related marketing claims, it is beneficial to meet consumers’ expectations. Producers have to decide if they orient their products to more modest or more critical consumer segments. While it is easier to implement lower standards, there is the risk to disappoint (and thereby lose) the most interesting target group of highly involved consumers characterised by some general doubts regarding food marketing claims.

The study is the first to demonstrate the existence of two consumer segments that differ in their expectations towards and acceptance of ag-related marketing claims for food products.

The objectives of this article are to develop a multiple‐item scale for measuring e‐service quality and to study the influence of perceived quality on consumer satisfaction levels and the level of web site loyalty.

First, there is an explanation of the main attributes of the concepts examined, with special attention being paid to the multi‐dimensional nature of the variables and the relationships between them. This is followed by an examination of the validation processes of the measuring instruments.

The validation process of scales suggested that perceived quality is a multidimensional construct: web design, customer service, assurance and order management; that perceived quality influences on satisfaction; and that satisfaction influences on consumer loyalty. Moreover, no differences in these conclusions were observed if the total sample is divided between buyers and information searchers.

First, the need to develop user‐friendly web sites which ease consumer purchasing and searching, thus creating a suitable framework for the generation of higher satisfaction and loyalty levels. Second, the web site manager should enhance service loyalty, customer sensitivity, personalised service and a quick response to complaints. Third, the web site should uphold sufficient security levels in communications and meet data protection requirements regarding the privacy. Lastly, the need for correct product delivery and product manipulation or service is recommended.

Most relevant studies about perceived quality in the internet have focused on web design aspects. Moreover, the existing literature regarding internet consumer behaviour has not fully analysed profits generated by higher perceived quality in terms of user satisfaction and loyalty.

The purpose of this paper is to determine if the nanoindentation technique is a reliable method and whether it can be used to measure the surface hardness (H) in friction stir welded aluminum alloys. In order to test the reliability of nanoindentation technique, nanohardness values for friction stir welded aluminum alloys were compared to microhardness values. Additionally, the onset of plasticity (yielding) is investigated.

Nanoindentation experiments were performed for the determination of onset on plasticity (yielding) and comparison of local mechanical properties of both welded alloys. In order to test the reliability of nanoindentation technique, nanohardness values for friction stir welded AA6082 were compared to microhardness values. The specimen was tested using two different instruments – a Vickers microhardness tester and a nanoindenter tester for fine scale evaluation of H.

The results of this study indicate that nanohardness values with a Berkovich indenter reliably correlate with Vickers microhardness values. Nanoindentation technique can provide reliable results for analyzing friction stir welded aluminum alloys. The welding process definitely affects the material mechanical properties.

Microhardness and nanohardness obtained values can be correlated carefully, regarding the similarities and the differences of the two above mentioned techniques.

The purpose of this paper is to examine an integrated model of perceived brand salience, perceived brand quality, perceived brand image and perceived brand loyalty in the Dead Sea tourism destination of Jordan from international tourists’ perspectives.

A structured and self-administered survey was employed targeting international tourists who were visiting the Dead Sea tourism destination. The authors delivered 300 questionnaires to international tourists, from which 237 were retained and valid for the analysis. A series of exploratory and confirmatory factor analyses was used to assess the research constructs dimensions, unidimensionality, validity and composite reliability. Structural path analysis was also used to test the hypothesized relationships of the research model.

The structural findings show that perceived brand salience has positively and significantly affected each of perceived brand quality and perceived destination loyalty. Perceived brand quality has positively and significantly affected each of perceived brand image-physical environment, perceived brand image-people characteristics and perceived destination loyalty. Each of perceived brand image-physical environment and perceived brand image-people characteristics has positively and significantly affected perceived destination loyalty. The structural findings indicate that perceived brand quality has exerted the strongest effect on each of perceived brand image-physical environment and perceived brand image-people characteristics. Further, the structural results show that R2 result of 0.48 indicates that 48 per cent of variation in perceived destination loyalty was caused by perceived brand quality, perceived brand image dimensions (physical environment and people characteristics) and perceived brand salience path.

This paper has examined only three drivers of destination loyalty; meanwhile, other factors such as tourists’ satisfaction and retention are potential areas of future research. Also, this study investigated international tourists’ perspectives in the Dead Sea tourism destination only, which means that its generalization potential to other destinations is limited. Therefore, comparative studies inside and outside Jordan’s tourism destinations are potential areas of future research. Other limitations and future research areas are also outlined.

The paper highlights the strategic importance of perceived brand quality and perceived brand image dimensions (physical environment and people characteristics) on perceived destination loyalty. Perceived brand quality acts as strong antecedent to perceived brand image dimensions, and perceived brand salience is an essential element of perceived destination loyalty. Perceived brand quality, perceived brand image dimensions and perceived brand salience are major drivers of perceived brand destination in an integrated manner. Also, perceived brand image dimensions of the physical environment and people friendless and kindness are also vital for creating perceived destination loyalty. Further, an integrated model of perceived brand salience, perceived brand quality, perceived brand image dimensions and destination loyalty is required by tourism organizations operating in the Dead Sea destination to win international tourists now and in the future.

This paper represents an early attempt to reveal and examine potential drivers of perceived destination loyalty in the Dead Sea, Jordan. Accordingly, it should shed more light into the strategic role of perceived brand quality, perceived brand salience and perceived brand image dimensions and how they affect perceived destination loyalty. Further, the paper is the first of its kind that investigated an integrated model of perceived brand salience and perceived destination loyalty via perceived brand quality and image dimensions from international tourist perspectives in Jordan. The main issue here is that tourism organizations operating in the Dead Sea tourism destination have now valuable empirical evidence concerning the drivers of perceived destination loyalty from international tourists’ perspectives.