Characterization by full-size testing of pultruded frame joints for the Startlink house

Presented in this paper are test results to determine the moment-rotation characteristics of joint details for a portal frame specific to a pultruded fiber reinforced polymer assembly for the Startlink house. Two joints having beam-to-column dowel connections, with and without extra adhesively bonding, were statically loaded in increments of moment or rotation to ultimate failure. The floor beam and stud column members are bespoke closed-sections developed for the Startlink lightweight building system. The serviceability design calculations for the demonstrator house to be constructed in Bourne, England, assumed the frame’s joints to be rigid. Clauses in EN 1993-1-8:2005 have been applied to classify the measured rotational stiffnesses against the rigid requirement, and an evaluation is made of the modes of failure with respect to the joint’s design moments. Only the joint with extra bonding between the mating surfaces of members is found to be classified as rigid. Both joints are shown to have an acceptable joint strength

Startlink building system and connections for fibre reinforced polymer structures

The research presented in this thesis examines various aspects on connections and joints in Pultruded Fibre Reinforced Polymeric (PFRP) structures. The work is divided into two experimental investigations on the determination of pin-bearing strength and the characterisation of dowel connections and joint for the Startlink Lightweight Building System (SLBS). To support the development of a strength formula for bearing resistance in bolted connections two pin-bearing strength test series were conducted to study the effects of load orientation and hot-wet conditioning. The limitations of existing standard test methods are exposed from a critical review to show that they do not specify the need for a clearance hole, the range of bolt diameters and PFRP thicknesses found in practice. Because the size of tension coupons is found to be too big to be cut from standard structural profiles an alternative test method, having a smaller coupon size, is needed for every pin-bearing strength to be quantified by testing. Reported in this thesis are test results using an in-house test method that requires a maximum blank coupon of 100 mm × 125 mm. Characteristic strength are determined using Annex D7 of Eurocode 0. Pin-bearing strengths for load orientations of 0, 5, 10, 20, 45 and 90o, to the direction of pultrusion are obtained for a web material taken from a standard wide flange section of 9.53 mm thick. In the test matrix there were four sizes of pin diameter from 9.7 mm to 25.4 mm and a minimum clearance hole of 1.6 mm. The in-house test method is shown to satisfactorily determine pin-bearing strength. Another finding from this study is that the Hankinson formula cannot be applied to establish pin-bearing strength at any orientation on knowing the two characteristic strengths at 0o and 90o. To characterise the effect of hot-wet conditioning 0, 45 and 90o specimens were immersed under water for 3000 hours at 40° C. It is found that the average reduction in characteristic strength is in the range of 18 to 31%. The extent of strength reduction is found to be independent of pin size, except when the diameter is 25.4 mm. The second experimental investigation is for fact finding strength tests towards the application of PFRP dowelling as a method of connection in SLBS. This innovative building system has been engineering for the execution of a FRP house that meets the requirements for code level 6. A series of static coupon-sized tests were conducted to determine the minimum resistance of dowel connections similar to those used in the Startlink house. These results were used to verify the structural engineering design calculations. Another sub-assembly test configuration was used to determine the moment-rotation characteristics of joint details for the portal frame in the SLBS house. Four different beam-to-column joints with dowel connections, and with and without adhesively bonded connections, were statically loaded so that their rotational stiffnesses and modes of failure could be determined. The main conclusions from this study are that: -- all joints had adequate strength against the design ULS moment; -- only when the joint had adhesive bonding between the overlapping beam and column members does the rotational stiffness approach the design rigid condition; -- when clearance holes are present the rotational stiffness is low and applying adhesive bonding around the dowels cannot remove this structural limitation

The world of β-glucans : a review of biological roles, applications and potential areas of research

Among many known and tested immunomodulators, polysaccharides isolated from various natural sources occupy a prominent position. An important group of these polysaccharides is represented by the homopolymers of β-glucose, called β-glucans. Their very low-to-negligible toxicity and immunomodulating effects show the promise it has in the therapy of a variety of infectious and cancer illnesses. Nowadays, the popularity of Glucans as food additive and a disease-modifying agent is increasing. Here, a review of the various biological roles, applications and potential areas of β-glucan research is presented. Also, a short introduction to current work by the Glucan group in Tromsø is provided. The goal has remained to understand and aptly present the diverse roles of β-glucans and pin-pointing the prospective areas of research, both on the receptor / biochemical level, and in clinical research. It seems that with the tide of modern medical research, gradually, β-glucans will take the position they deserve in diagnostic and preventive medicine

Pin-bearing strengths for the design of bolted connections with pultruded material

Presented in this paper are test results for the determination of the pin-bearing strength of pultruded fibre reinforced polymer material required to calculate the bearing resistance of bolted connections under factored loading. It is well-known [1] that single-bolted and multi-bolted connections of pultruded material fail ultimately in a number of distinct failure modes (e.g. bearing, shear-out, cleavage, net-tension and block shear). Bearing is the only one of the mechanisms that does not give a brittle failure response, and can provide the connection with a degree of damage tolerance, which is desirable. The design calculation for bearing resistance is given by the projected area of bearing bolt times the specified bearing strength (Fbr) in the direction of the connection force, which is then multiplied by the number of bolts. In [2] a historical review on the determination of Fbr, is reported, and evaluated to show that there is a lack of consistency in how this strength has been measured, and much uncertainty on what values are to be taken in the resistance calculations. A comparison in [2] of pin-bearing strength measurements, based on the two test methodologies given in ASTM D5764 [3] and BS EN ISO 13706 [4], showed that the ‘timber’ approach is suitable when there is a restriction on the size of coupon specimen that can be cut from a pultruded section. Presented are new test results for pin-bearing strengths when is equal to 0, 45 or 90 degrees, using the ‘timber’ approach. An evaluation of the data (with varying pin diameter-to-thickness ratio) is made with the aim of establishing how we establish a specified strength for the safe and reliable design of bolted connections

Pin-bearing strengths for bolted connections in fibre-reinforced polymer structures

Presented in this paper are pin-bearing strengths for pultruded fibre-reinforced polymer materials that are required in order to check the bearing resistance when designing bolted connections. For steel pin diameters up to 16 mm, equivalent test results, at room temperature, using the European standard test method BS EN 13706-2 and another test method (such as ASTM D 5764) are shown not to be significantly different. As the latter method uses much smaller specimen blanks, new pin-bearing strengths can be determined for the web material in a 203 x 203 x 9.5 mm wide flange shape, with the connection force at 0 degrees, 45 degrees or 90 degrees to the direction of pultrusion. An evaluation is made of the test results and recommendations are given on how pin-bearing strengths are to be determined so that they will match the geometries of bolted connections and connection forces found in practice

The Two-Sidedness of Society : Actor-structure in the Research Programmes and the Applications of Three Approaches

Samhällsvetenskapliga portalfigurer som Durkheim, Marx och Weber har medverkat i diskussionen om aktör och struktur. Diskussionen om intentioner; agerande och samhällsstrukturer pågår fortfarande. Om de samhällsvetenskapliga fenomenen utgår från individen – aktören – och/eller dess omgivning - strukturen - är en evig fråga. Denna avhandling är ett bidrag till den moderna diskussionen om aktör och struktur. Syftet är att analysera problemkomplexet aktör-struktur. Många tidigare studier i genren är abstrakta och generella. I detta arbete studeras också samhällsforskares tillämpning. Efter analyser av den aktörsteoretiska ansatsen (statsvetaren Axel Hadenius' forskning, den strukturteoretiska ansatsen (sociologen Bruce Mayhews forskning), samt a ansatsen (statsvetaren Bo Rothsteins forskning), samt redovisas ett preciserat förhållningssätt till problemkomplexet. Studiens utgångspunkt är att både den ensidiga aktörsteoretiska ansatsen och den ensidiga strukturteoretiska ansatsen kommer att uppvisa brister. De respektive ensidiga ansatserna antas inte brista främst på grund av sin ensidighet, vilket flera företrädare för den aktör-strukturteoretiska ansatsen hävdar. Utifrån avhandlingens vägledande analysram förväntas de respektive ensidiga ansatsernas filosofier, teorier och förklaringar brista på så sätt att företrädarnas programförklaringar inte stämmer överens med företrädarnas tillämpningar. Därmed uppfyller de ensidiga ansatsernas företrädare inte det grundläggande kravet på vetenskaplig klarhet. Av analysen framgår att det i den aktörsteoretiska ansatsens tillämpning också återfinns strukturfaktorer av ett slag som ansatsens företrädare programmatiskt vill utesluta. I den tillämpade strukturteoretiska ansatsen återfinns aktörsfaktorer. Också den aktör-strukturteoretiska ansats som analyseras uppvisar brister i överensstämmelse mellan programförklaring och tillämpning. Resultaten tas till intäkt för att överge både den individualism som den aktörsteoretiska ansatsen vilar på och den strukturalism sätts i detta arbete den filosofiska antagande att den samhälleliga verkligheten innehåller både aktör och struktur, Antagandet om samhällets tvåsidighet utgör en viktig grund för den preciserande aktör-strukturteoretiska ansats som är studiens övergripande slutsats.This thesis is a contribution to the age-old discussion in the social sciences about actor and structure. From the outset it is argued that the question of actor and structure constitutes a complexity of problems which contains philosophical, theoretical and explanatory elements. Different ways of comprehending the complexity of problems constitute a watershed between research approaches. The three main approaches are the actor theoretical approach, the structural theoretical approach and 1he actor-structural theoretical approach. The purpose of this study is to analyse these three approaches and thereby present a fruitful approach to the complexity of problems. The author adopts the combined actor-structural theoretical approach from the start, but not in an uncritical and self-evident manner. This study is based on two lines of argumentation. Firstly, it is stipulated that a social scientist's research programme on actor and structure should be consistent With the researcher's application. Secondly, it is stipulated that social reality consists of both actor and s1ructure, and that actor and  structure do not mean the same thing. The author's suggestion is that this idea about the two-sidedness of soc iety is a prerequisite for interna! consistency. Hence, traces of both actor and structure should a lso be found in the applications of the two one-sided approaches. In order to discern the one-sided actor theoretical approach, three ideas are stipulated as philosophy, theory and explanation in a specified ideal type: methodological individualism, instrumental rationality and intentional explanation. These ideas are present in the research programme of the chosen representative of the actor theoretical approach, the Swedish political scientist Axel Hadenius. It is found that Hadenius' application does not correspond with his research programme. In his application. factors occur that are not totally reducible to facts aboul separale or aggregated individuals. In order to discern the one-sided sructural theoretical approach, three ideas are stipulated as philosophy. theory and explanation in a specified ideal type: structuralism, theoretical relations between structures and nomothetical-deductive explanations with structures. These ideas are present in the research programme of the chosen representative of the structural theoretical approach, the American sociologi st Bruce Mayhew. It is found that Mayhew's application does not correspond with his research programme. In his application, fac1s about separate or aggregated individuals occur. The three ideas behind the ideal type actor-structural theoretical approach are two-sided level realism, theoretical actor-structural relations and actor-structural explanation. These ideas are present in the research programme of the chosen representative of the actor-structural theoretical approach, the Swedish political scientist Bo Rothstein, even if there are also traces leading off in other directions. Finally, the testing of the occurrence of the preliminary actor-structural approach in the three research approaches is combined with the elabora1ion of philosophy, theory and explana1ion in the specified actorstructural theoretical approach. The latter approach constitutes the author's stand on the complexity of problems of actor and structure. The philosophy in the specified approach, two-sided leve! realism, is allegedly composed of three closely related ideas: actual closeness between actor and structure, situational irreducibility, and the relational concept of social structure. The idea of the theoretical relation between actor and structure is allegedly composed of three closely related ideas: empirical openness, analytical dualism and generative mechanisms. All are, in tum, closely related to the three ideas of the two-sided leve! realism, as well as to the idea of actor-structural explanation. The specified approach lays the foundations for clarity in terms of internat logical congruence between research programme and application